First pass getting user documentation in the IDE

Track various symbols in the parse stage of Slang
First pass getting deeper LSP into IDE
2026-01-02 19:14:58 -07:00 · 2026-01-02 17:06:43 -07:00 · 2026-01-02 16:57:06 -07:00
14 changed files with 1154 additions and 54 deletions
--- a/csharp_mod/Extensions.cs
+++ b/csharp_mod/Extensions.cs
@@ -207,4 +207,34 @@ public static unsafe class SlangExtensions
        Ffi.free_docs_vec(vec);
        return toReturn;
    }
+
+    public static unsafe List<Symbol> ToList(this Vec_FfiSymbolInfo_t vec)
+    {
+        var toReturn = new List<Symbol>((int)vec.len);
+
+        var currentPtr = vec.ptr;
+
+        for (int i = 0; i < (int)vec.len; i++)
+        {
+            var item = currentPtr[i];
+
+            toReturn.Add(
+                new Slang.Symbol
+                {
+                    Name = item.name.AsString(),
+                    Kind = (SymbolKind)item.kind_data.kind,
+                    Span = new Slang.Range
+                    {
+                        StartLine = item.span.start_line,
+                        StartCol = item.span.start_col,
+                        EndLine = item.span.end_line,
+                        EndCol = item.span.end_col,
+                    },
+                    Description = item.description.AsString(),
+                }
+            );
+        }
+
+        return toReturn;
+    }
 }
--- a/csharp_mod/FfiGlue.cs
+++ b/csharp_mod/FfiGlue.cs
@@ -147,6 +147,51 @@ public unsafe partial class Ffi {
        slice_ref_uint16_t input);
 }

+[StructLayout(LayoutKind.Sequential, Size = 12)]
+public unsafe struct FfiSymbolKindData_t {
+    public UInt32 kind;
+
+    public UInt32 arg_count;
+
+    public UInt32 syscall_type;
+}
+
+[StructLayout(LayoutKind.Sequential, Size = 80)]
+public unsafe struct FfiSymbolInfo_t {
+    public Vec_uint8_t name;
+
+    public FfiSymbolKindData_t kind_data;
+
+    public FfiRange_t span;
+
+    public Vec_uint8_t description;
+}
+
+/// <summary>
+/// Same as [<c>Vec<T></c>][<c>rust::Vec</c>], but with guaranteed <c>#[repr(C)]</c> layout
+/// </summary>
+[StructLayout(LayoutKind.Sequential, Size = 24)]
+public unsafe struct Vec_FfiSymbolInfo_t {
+    public FfiSymbolInfo_t * ptr;
+
+    public UIntPtr len;
+
+    public UIntPtr cap;
+}
+
+[StructLayout(LayoutKind.Sequential, Size = 48)]
+public unsafe struct FfiDiagnosticsAndSymbols_t {
+    public Vec_FfiDiagnostic_t diagnostics;
+
+    public Vec_FfiSymbolInfo_t symbols;
+}
+
+public unsafe partial class Ffi {
+    [DllImport(RustLib, ExactSpelling = true)] public static unsafe extern
+    FfiDiagnosticsAndSymbols_t diagnose_source_with_symbols (
+        slice_ref_uint16_t input);
+}
+
 [StructLayout(LayoutKind.Sequential, Size = 48)]
 public unsafe struct FfiDocumentedItem_t {
    public Vec_uint8_t item_name;
@@ -184,6 +229,12 @@ public unsafe partial class Ffi {
        Vec_FfiDiagnostic_t v);
 }

+public unsafe partial class Ffi {
+    [DllImport(RustLib, ExactSpelling = true)] public static unsafe extern
+    void free_ffi_diagnostics_and_symbols (
+        FfiDiagnosticsAndSymbols_t v);
+}
+
 [StructLayout(LayoutKind.Sequential, Size = 64)]
 public unsafe struct FfiToken_t {
    public Vec_uint8_t tooltip;
--- a/csharp_mod/Formatter.cs
+++ b/csharp_mod/Formatter.cs
@@ -171,18 +171,17 @@ public class SlangFormatter : ICodeFormatter
                return;

            // Running this potentially CPU intensive work on a background thread.
-            var dict = await Task.Run(
+            var (diagnostics, symbols) = await Task.Run(
                () =>
                {
-                    return Marshal
-                        .DiagnoseSource(inputSrc)
-                        .GroupBy(d => d.Range.StartLine)
-                        .ToDictionary(g => g.Key);
+                    return Marshal.DiagnoseSourceWithSymbols(inputSrc);
                },
                cancellationToken
            );

-            ApplyDiagnostics(dict);
+            var dict = diagnostics.GroupBy(d => d.Range.StartLine).ToDictionary(g => g.Key);
+
+            ApplyDiagnosticsAndSymbols(dict, symbols);

            // If we have valid code, update the IC10 output
            if (dict.Count > 0)
@@ -266,11 +265,11 @@ public class SlangFormatter : ICodeFormatter
    }

    /// <summary>
-    /// Takes diagnostics from the Rust FFI compiler and applies it as semantic tokens to the
+    /// Takes diagnostics and symbols from the Rust FFI compiler and applies them as semantic tokens to the
    /// source in this editor.
    /// This runs on the Main Thread
    /// </summary>
-    private void ApplyDiagnostics(Dictionary<uint, IGrouping<uint, Diagnostic>> dict)
+    private void ApplyDiagnosticsAndSymbols(Dictionary<uint, IGrouping<uint, Diagnostic>> dict, List<Symbol> symbols)
    {
        HashSet<uint> linesToRefresh;

@@ -289,6 +288,12 @@ public class SlangFormatter : ICodeFormatter
        {
            linesToRefresh = new HashSet<uint>(dict.Keys);
            linesToRefresh.UnionWith(_linesWithErrors);
+
+            // Also add lines with symbols that may have been modified
+            foreach (var symbol in symbols)
+            {
+                linesToRefresh.Add(symbol.Span.StartLine);
+            }
        }

        _lastLineCount = this.Lines.Count;
@@ -328,9 +333,49 @@ public class SlangFormatter : ICodeFormatter
                }
            }

+            // 3. Add symbol tooltips for symbols on this line
+            foreach (var symbol in symbols)
+            {
+                if (symbol.Span.StartLine == lineIndex)
+                {
+                    var column = (int)symbol.Span.StartCol;
+                    var length = Math.Max(1, (int)(symbol.Span.EndCol - symbol.Span.StartCol));
+
+                    // If there's already a token at this position (from syntax highlighting), use it
+                    // Otherwise, create a new token for the symbol
+                    if (allTokensDict.ContainsKey(column))
+                    {
+                        // Update existing token with symbol tooltip
+                        var existingToken = allTokensDict[column];
+                        allTokensDict[column] = new SemanticToken(
+                            line: existingToken.Line,
+                            column: existingToken.Column,
+                            length: existingToken.Length,
+                            type: existingToken.Type,
+                            style: existingToken.Style,
+                            data: symbol.Description, // Use symbol description as tooltip
+                            isError: existingToken.IsError
+                        );
+                    }
+                    else
+                    {
+                        // Create new token for symbol
+                        allTokensDict[column] = new SemanticToken(
+                            line: (int)lineIndex,
+                            column,
+                            length,
+                            type: 0,
+                            style: ColorIdentifier,
+                            data: symbol.Description,
+                            isError: false
+                        );
+                    }
+                }
+            }
+
            var allTokens = allTokensDict.Values.ToList();

-            // 3. Update the line (this clears existing tokens and uses the list we just built)
+            // 4. Update the line (this clears existing tokens and uses the list we just built)
            line.Update(allTokens);

            ReattachMetadata(line, allTokens);
@@ -339,6 +384,16 @@ public class SlangFormatter : ICodeFormatter
        _linesWithErrors = new HashSet<uint>(dict.Keys);
    }

+    /// <summary>
+    /// Takes diagnostics from the Rust FFI compiler and applies it as semantic tokens to the
+    /// source in this editor.
+    /// This runs on the Main Thread
+    /// </summary>
+    private void ApplyDiagnostics(Dictionary<uint, IGrouping<uint, Diagnostic>> dict)
+    {
+        ApplyDiagnosticsAndSymbols(dict, new List<Symbol>());
+    }
+
    // Helper to map SemanticToken data (tooltips/errors) back to the tokens in the line
    private void ReattachMetadata(StyledLine line, List<SemanticToken> semanticTokens)
    {
--- a/csharp_mod/Marshal.cs
+++ b/csharp_mod/Marshal.cs
@@ -47,6 +47,33 @@ public struct SourceMapEntry
    }
 }

+public struct Symbol
+{
+    public string Name;
+    public Range Span;
+    public SymbolKind Kind;
+    public string Description;
+
+    public override string ToString()
+    {
+        return $"{Kind}: {Name} at {Span}";
+    }
+}
+
+public enum SymbolKind
+{
+    Function = 0,
+    Syscall = 1,
+    Variable = 2,
+}
+
+public struct SymbolData
+{
+    public uint Kind;
+    public uint ArgCount;
+    public uint SyscallType; // 0=System, 1=Math
+}
+
 public static class Marshal
 {
    private static IntPtr _libraryHandle = IntPtr.Zero;
@@ -164,6 +191,59 @@ public static class Marshal
        }
    }

+    public static unsafe (List<Diagnostic>, List<Symbol>) DiagnoseSourceWithSymbols(string inputString)
+    {
+        if (string.IsNullOrEmpty(inputString) || !EnsureLibLoaded())
+        {
+            return (new(), new());
+        }
+
+        fixed (char* ptrInput = inputString)
+        {
+            var input = new slice_ref_uint16_t
+            {
+                ptr = (ushort*)ptrInput,
+                len = (UIntPtr)inputString.Length,
+            };
+
+            var result = Ffi.diagnose_source_with_symbols(input);
+
+            // Convert diagnostics
+            var diagnostics = result.diagnostics.ToList();
+
+            // Convert symbols
+            var symbols = new List<Symbol>();
+            var symbolPtr = result.symbols.ptr;
+            var symbolCount = (int)result.symbols.len;
+
+            for (int i = 0; i < symbolCount; i++)
+            {
+                var ffiSymbol = symbolPtr[i];
+                var kind = (SymbolKind)ffiSymbol.kind_data.kind;
+
+                // Use the actual description from the FFI (includes doc comments and syscall docs)
+                var description = ffiSymbol.description.AsString();
+
+                symbols.Add(new Symbol
+                {
+                    Name = ffiSymbol.name.AsString(),
+                    Kind = kind,
+                    Span = new Range(
+                        ffiSymbol.span.start_line,
+                        ffiSymbol.span.start_col,
+                        ffiSymbol.span.end_line,
+                        ffiSymbol.span.end_col
+                    ),
+                    Description = description,
+                });
+            }
+
+            Ffi.free_ffi_diagnostics_and_symbols(result);
+
+            return (diagnostics, symbols);
+        }
+    }
+
    public static unsafe List<SemanticToken> TokenizeLine(string inputString)
    {
        if (string.IsNullOrEmpty(inputString) || !EnsureLibLoaded())
--- a/rust_compiler/Cargo.lock
+++ b/rust_compiler/Cargo.lock
@@ -173,7 +173,7 @@ dependencies = [
 "proc-macro-crate",
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
@@ -224,9 +224,9 @@ checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"

 [[package]]
 name = "clap"
-version = "4.5.53"
+version = "4.5.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9e340e012a1bf4935f5282ed1436d1489548e8f72308207ea5df0e23d2d03f8"
+checksum = "c6e6ff9dcd79cff5cd969a17a545d79e84ab086e444102a591e288a8aa3ce394"
 dependencies = [
 "clap_builder",
 "clap_derive",
@@ -234,9 +234,9 @@ dependencies = [

 [[package]]
 name = "clap_builder"
-version = "4.5.53"
+version = "4.5.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d76b5d13eaa18c901fd2f7fca939fefe3a0727a953561fefdf3b2922b8569d00"
+checksum = "fa42cf4d2b7a41bc8f663a7cab4031ebafa1bf3875705bfaf8466dc60ab52c00"
 dependencies = [
 "anstream",
 "anstyle",
@@ -253,7 +253,7 @@ dependencies = [
 "heck",
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
@@ -523,9 +523,9 @@ checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"

 [[package]]
 name = "itoa"
-version = "1.0.15"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+checksum = "92ecc6618181def0457392ccd0ee51198e065e016d1d527a7ac1b6dc7c1f09d2"

 [[package]]
 name = "js-sys"
@@ -571,7 +571,7 @@ dependencies = [
 "regex-automata",
 "regex-syntax",
 "rustc_version",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
@@ -726,9 +726,9 @@ dependencies = [

 [[package]]
 name = "proc-macro2"
-version = "1.0.103"
+version = "1.0.104"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
+checksum = "9695f8df41bb4f3d222c95a67532365f569318332d03d5f3f67f37b20e6ebdf0"
 dependencies = [
 "unicode-ident",
 ]
@@ -909,12 +909,6 @@ version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"

-[[package]]
-name = "ryu"
-version = "1.0.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
-
 [[package]]
 name = "safer-ffi"
 version = "0.1.13"
@@ -992,20 +986,20 @@ checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
 name = "serde_json"
-version = "1.0.145"
+version = "1.0.148"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "402a6f66d8c709116cf22f558eab210f5a50187f702eb4d7e5ef38d9a7f1c79c"
+checksum = "3084b546a1dd6289475996f182a22aba973866ea8e8b02c51d9f46b1336a22da"
 dependencies = [
 "itoa",
 "memchr",
- "ryu",
 "serde",
 "serde_core",
+ "zmij",
 ]

 [[package]]
@@ -1016,7 +1010,7 @@ checksum = "175ee3e80ae9982737ca543e96133087cbd9a485eecc3bc4de9c1a37b47ea59c"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
@@ -1108,9 +1102,9 @@ dependencies = [

 [[package]]
 name = "syn"
-version = "2.0.111"
+version = "2.0.112"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "390cc9a294ab71bdb1aa2e99d13be9c753cd2d7bd6560c77118597410c4d2e87"
+checksum = "21f182278bf2d2bcb3c88b1b08a37df029d71ce3d3ae26168e3c653b213b99d4"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -1153,7 +1147,7 @@ checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]

 [[package]]
@@ -1185,9 +1179,9 @@ dependencies = [

 [[package]]
 name = "toml_datetime"
-version = "0.7.4+spec-1.0.0"
+version = "0.7.5+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe3cea6b2aa3b910092f6abd4053ea464fab5f9c170ba5e9a6aead16ec4af2b6"
+checksum = "92e1cfed4a3038bc5a127e35a2d360f145e1f4b971b551a2ba5fd7aedf7e1347"
 dependencies = [
 "serde_core",
 ]
@@ -1206,9 +1200,9 @@ dependencies = [

 [[package]]
 name = "toml_parser"
-version = "1.0.5+spec-1.0.0"
+version = "1.0.6+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c03bee5ce3696f31250db0bbaff18bc43301ce0e8db2ed1f07cbb2acf89984c"
+checksum = "a3198b4b0a8e11f09dd03e133c0280504d0801269e9afa46362ffde1cbeebf44"
 dependencies = [
 "winnow",
 ]
@@ -1303,7 +1297,7 @@ dependencies = [
 "bumpalo",
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 "wasm-bindgen-shared",
 ]

@@ -1471,5 +1465,11 @@ checksum = "d8a8d209fdf45cf5138cbb5a506f6b52522a25afccc534d1475dad8e31105c6a"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.111",
+ "syn 2.0.112",
 ]
+
+[[package]]
+name = "zmij"
+version = "1.0.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "317f17ff091ac4515f17cc7a190d2769a8c9a96d227de5d64b500b01cda8f2cd"
--- a/rust_compiler/libs/compiler/src/lib.rs
+++ b/rust_compiler/libs/compiler/src/lib.rs
@@ -1,6 +1,8 @@
+pub mod symbols;
 #[cfg(test)]
 mod test;
 mod v1;
 mod variable_manager;

+pub use symbols::{CompilationMetadata, SymbolInfo, SymbolKind, SyscallType};
 pub use v1::{CompilationResult, Compiler, CompilerConfig, Error};
--- a/rust_compiler/libs/compiler/src/symbols.rs
+++ b/rust_compiler/libs/compiler/src/symbols.rs
@@ -0,0 +1,343 @@
+use helpers::Span;
+use std::borrow::Cow;
+
+/// Represents a symbol (function, syscall, variable, etc.) that can be referenced in code.
+/// Designed to be LSP-compatible for easy integration with language servers.
+#[derive(Debug, Clone)]
+pub struct SymbolInfo<'a> {
+    /// The name of the symbol
+    pub name: Cow<'a, str>,
+    /// The kind of symbol and associated metadata
+    pub kind: SymbolKind<'a>,
+    /// The source location of this symbol (for IDE features)
+    pub span: Option<Span>,
+    /// Optional description for tooltips and documentation
+    pub description: Option<Cow<'a, str>>,
+}
+
+impl<'a> SymbolInfo<'a> {
+    /// Converts to an LSP SymbolInformation for protocol compatibility.
+    pub fn to_lsp_symbol_information(&self, uri: lsp_types::Uri) -> lsp_types::SymbolInformation {
+        lsp_types::SymbolInformation {
+            name: self.name.to_string(),
+            kind: self.kind.to_lsp_symbol_kind(),
+            #[allow(deprecated)]
+            deprecated: None,
+            location: lsp_types::Location {
+                uri,
+                range: self.span.as_ref().map(|s| (*s).into()).unwrap_or_default(),
+            },
+            container_name: None,
+            tags: None,
+        }
+    }
+
+    /// Converts to an LSP CompletionItem for autocomplete.
+    pub fn to_lsp_completion_item(&self) -> lsp_types::CompletionItem {
+        lsp_types::CompletionItem {
+            label: self.name.to_string(),
+            kind: Some(self.kind.to_lsp_completion_kind()),
+            documentation: self
+                .description
+                .as_ref()
+                .map(|d| lsp_types::Documentation::String(d.to_string())),
+            detail: Some(self.kind.detail_string()),
+            ..Default::default()
+        }
+    }
+}
+
+/// Discriminates between different kinds of symbols.
+#[derive(Debug, Clone)]
+pub enum SymbolKind<'a> {
+    /// A user-defined function
+    Function {
+        /// Names of parameters in order
+        parameters: Vec<Cow<'a, str>>,
+        /// Type hint for the return type (if applicable)
+        return_type: Option<Cow<'a, str>>,
+    },
+    /// A system or math syscall
+    Syscall {
+        /// Whether it's a System or Math syscall
+        syscall_type: SyscallType,
+        /// Number of expected arguments
+        argument_count: usize,
+    },
+    /// A variable declaration
+    Variable {
+        /// Type hint for the variable (if applicable)
+        type_hint: Option<Cow<'a, str>>,
+    },
+}
+
+impl<'a> SymbolKind<'a> {
+    /// Converts to LSP SymbolKind for protocol compatibility.
+    fn to_lsp_symbol_kind(&self) -> lsp_types::SymbolKind {
+        match self {
+            SymbolKind::Function { .. } => lsp_types::SymbolKind::FUNCTION,
+            SymbolKind::Syscall { .. } => lsp_types::SymbolKind::FUNCTION, // Syscalls are function-like
+            SymbolKind::Variable { .. } => lsp_types::SymbolKind::VARIABLE,
+        }
+    }
+
+    /// Converts to LSP CompletionItemKind for autocomplete filtering.
+    fn to_lsp_completion_kind(&self) -> lsp_types::CompletionItemKind {
+        match self {
+            SymbolKind::Function { .. } => lsp_types::CompletionItemKind::FUNCTION,
+            SymbolKind::Syscall { .. } => lsp_types::CompletionItemKind::FUNCTION,
+            SymbolKind::Variable { .. } => lsp_types::CompletionItemKind::VARIABLE,
+        }
+    }
+
+    /// Returns a human-readable detail string for display in IDEs.
+    fn detail_string(&self) -> String {
+        match self {
+            SymbolKind::Function {
+                parameters,
+                return_type,
+            } => {
+                let params = parameters
+                    .iter()
+                    .map(|p| p.to_string())
+                    .collect::<Vec<_>>()
+                    .join(", ");
+                let ret = return_type
+                    .as_ref()
+                    .map(|t| format!(" -> {}", t))
+                    .unwrap_or_default();
+                format!("fn({}){}", params, ret)
+            }
+            SymbolKind::Syscall {
+                syscall_type,
+                argument_count,
+            } => {
+                format!(
+                    "{}(... {} args)",
+                    match syscall_type {
+                        SyscallType::System => "syscall",
+                        SyscallType::Math => "math",
+                    },
+                    argument_count
+                )
+            }
+            SymbolKind::Variable { type_hint } => type_hint
+                .as_ref()
+                .map(|t| t.to_string())
+                .unwrap_or_else(|| "var".to_string()),
+        }
+    }
+}
+
+/// Distinguishes between System and Math syscalls.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SyscallType {
+    System,
+    Math,
+}
+
+/// Metadata collected during compilation, including all referenced symbols.
+#[derive(Debug, Default)]
+pub struct CompilationMetadata<'a> {
+    /// All symbols encountered during compilation (functions, syscalls, variables)
+    pub symbols: Vec<SymbolInfo<'a>>,
+}
+
+impl<'a> CompilationMetadata<'a> {
+    /// Creates a new empty compilation metadata.
+    pub fn new() -> Self {
+        Self {
+            symbols: Vec::new(),
+        }
+    }
+
+    /// Adds a symbol to the metadata.
+    pub fn add_symbol(&mut self, symbol: SymbolInfo<'a>) {
+        self.symbols.push(symbol);
+    }
+
+    /// Adds a function symbol.
+    pub fn add_function(
+        &mut self,
+        name: Cow<'a, str>,
+        parameters: Vec<Cow<'a, str>>,
+        span: Option<Span>,
+    ) {
+        self.add_function_with_doc(name, parameters, span, None);
+    }
+
+    /// Adds a function symbol with optional doc comment.
+    pub fn add_function_with_doc(
+        &mut self,
+        name: Cow<'a, str>,
+        parameters: Vec<Cow<'a, str>>,
+        span: Option<Span>,
+        description: Option<Cow<'a, str>>,
+    ) {
+        self.add_symbol(SymbolInfo {
+            name,
+            kind: SymbolKind::Function {
+                parameters,
+                return_type: None,
+            },
+            span,
+            description,
+        });
+    }
+
+    /// Adds a syscall symbol.
+    pub fn add_syscall(
+        &mut self,
+        name: Cow<'a, str>,
+        syscall_type: SyscallType,
+        argument_count: usize,
+        span: Option<Span>,
+    ) {
+        self.add_syscall_with_doc(name, syscall_type, argument_count, span, None);
+    }
+
+    /// Adds a syscall symbol with optional doc comment.
+    pub fn add_syscall_with_doc(
+        &mut self,
+        name: Cow<'a, str>,
+        syscall_type: SyscallType,
+        argument_count: usize,
+        span: Option<Span>,
+        description: Option<Cow<'a, str>>,
+    ) {
+        self.add_symbol(SymbolInfo {
+            name,
+            kind: SymbolKind::Syscall {
+                syscall_type,
+                argument_count,
+            },
+            span,
+            description,
+        });
+    }
+
+    /// Adds a variable symbol.
+    pub fn add_variable(&mut self, name: Cow<'a, str>, span: Option<Span>) {
+        self.add_variable_with_doc(name, span, None);
+    }
+
+    /// Adds a variable symbol with optional doc comment.
+    pub fn add_variable_with_doc(
+        &mut self,
+        name: Cow<'a, str>,
+        span: Option<Span>,
+        description: Option<Cow<'a, str>>,
+    ) {
+        self.add_symbol(SymbolInfo {
+            name,
+            kind: SymbolKind::Variable { type_hint: None },
+            span,
+            description,
+        });
+    }
+
+    /// Returns all symbols of a specific kind.
+    pub fn symbols_of_kind(&self, kind: &str) -> Vec<&SymbolInfo<'a>> {
+        self.symbols
+            .iter()
+            .filter(|sym| match (&sym.kind, kind) {
+                (SymbolKind::Function { .. }, "function") => true,
+                (SymbolKind::Syscall { .. }, "syscall") => true,
+                (SymbolKind::Variable { .. }, "variable") => true,
+                _ => false,
+            })
+            .collect()
+    }
+
+    /// Converts all symbols to LSP SymbolInformation for protocol compatibility.
+    pub fn to_lsp_symbols(&self, uri: lsp_types::Uri) -> Vec<lsp_types::SymbolInformation> {
+        self.symbols
+            .iter()
+            .map(|sym| sym.to_lsp_symbol_information(uri.clone()))
+            .collect()
+    }
+
+    /// Converts all symbols to LSP CompletionItems for autocomplete.
+    pub fn to_lsp_completion_items(&self) -> Vec<lsp_types::CompletionItem> {
+        self.symbols
+            .iter()
+            .map(|sym| sym.to_lsp_completion_item())
+            .collect()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_metadata_creation() {
+        let metadata = CompilationMetadata::new();
+        assert!(metadata.symbols.is_empty());
+    }
+
+    #[test]
+    fn test_add_function_symbol() {
+        let mut metadata = CompilationMetadata::new();
+        metadata.add_function("test_func".into(), vec!["x".into(), "y".into()], None);
+        assert_eq!(metadata.symbols.len(), 1);
+        assert_eq!(metadata.symbols[0].name, "test_func");
+    }
+
+    #[test]
+    fn test_add_syscall_symbol() {
+        let mut metadata = CompilationMetadata::new();
+        metadata.add_syscall("hash".into(), SyscallType::System, 1, None);
+        assert_eq!(metadata.symbols.len(), 1);
+        assert_eq!(metadata.symbols[0].name, "hash");
+    }
+
+    #[test]
+    fn test_symbols_of_kind() {
+        let mut metadata = CompilationMetadata::new();
+        metadata.add_function("func1".into(), vec![], None);
+        metadata.add_syscall("hash".into(), SyscallType::System, 1, None);
+        metadata.add_variable("x".into(), None);
+
+        let functions = metadata.symbols_of_kind("function");
+        assert_eq!(functions.len(), 1);
+
+        let syscalls = metadata.symbols_of_kind("syscall");
+        assert_eq!(syscalls.len(), 1);
+
+        let variables = metadata.symbols_of_kind("variable");
+        assert_eq!(variables.len(), 1);
+    }
+
+    #[test]
+    fn test_lsp_completion_items() {
+        let mut metadata = CompilationMetadata::new();
+        metadata.add_function("test_func".into(), vec![], None);
+        metadata.add_syscall("hash".into(), SyscallType::System, 1, None);
+        metadata.add_variable("x".into(), None);
+
+        let completions = metadata.to_lsp_completion_items();
+        assert_eq!(completions.len(), 3);
+
+        // Verify function
+        assert_eq!(completions[0].label, "test_func");
+        assert_eq!(
+            completions[0].kind,
+            Some(lsp_types::CompletionItemKind::FUNCTION)
+        );
+
+        // Verify syscall
+        assert_eq!(completions[1].label, "hash");
+        assert_eq!(
+            completions[1].kind,
+            Some(lsp_types::CompletionItemKind::FUNCTION)
+        );
+
+        // Verify variable
+        assert_eq!(completions[2].label, "x");
+        assert_eq!(
+            completions[2].kind,
+            Some(lsp_types::CompletionItemKind::VARIABLE)
+        );
+    }
+}
--- a/rust_compiler/libs/compiler/src/test/mod.rs
+++ b/rust_compiler/libs/compiler/src/test/mod.rs
@@ -47,6 +47,15 @@ macro_rules! compile {
            output,
        }
    }};
+
+    (metadata $source:expr) => {{
+        let compiler = crate::Compiler::new(
+            parser::Parser::new(tokenizer::Tokenizer::from($source)),
+            None,
+        );
+        let res = compiler.compile();
+        res.metadata
+    }};
 }
 mod binary_expression;
 mod branching;
@@ -61,5 +70,6 @@ mod loops;
 mod math_syscall;
 mod negation_priority;
 mod scoping;
+mod symbol_documentation;
 mod syscall;
 mod tuple_literals;
--- a/rust_compiler/libs/compiler/src/test/symbol_documentation.rs
+++ b/rust_compiler/libs/compiler/src/test/symbol_documentation.rs
@@ -0,0 +1,120 @@
+#[cfg(test)]
+mod test {
+    use anyhow::Result;
+
+    #[test]
+    fn test_variable_doc_comment() -> Result<()> {
+        let metadata = compile!(metadata "/// this is a documented variable\nlet myVar = 42;");
+
+        let var_symbol = metadata
+            .symbols
+            .iter()
+            .find(|s| s.name == "myVar")
+            .expect("myVar symbol not found");
+
+        assert_eq!(
+            var_symbol.description.as_ref().map(|d| d.as_ref()),
+            Some("this is a documented variable")
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn test_const_doc_comment() -> Result<()> {
+        let metadata = compile!(metadata "/// const documentation\nconst myConst = 100;");
+
+        let const_symbol = metadata
+            .symbols
+            .iter()
+            .find(|s| s.name == "myConst")
+            .expect("myConst symbol not found");
+
+        assert_eq!(
+            const_symbol.description.as_ref().map(|d| d.as_ref()),
+            Some("const documentation")
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn test_device_doc_comment() -> Result<()> {
+        let metadata = compile!(metadata "/// device documentation\ndevice myDevice = \"d0\";");
+
+        let device_symbol = metadata
+            .symbols
+            .iter()
+            .find(|s| s.name == "myDevice")
+            .expect("myDevice symbol not found");
+
+        assert_eq!(
+            device_symbol.description.as_ref().map(|d| d.as_ref()),
+            Some("device documentation")
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn test_function_doc_comment() -> Result<()> {
+        let metadata = compile!(metadata "/// function documentation\nfn test() { }");
+
+        let fn_symbol = metadata
+            .symbols
+            .iter()
+            .find(|s| s.name == "test")
+            .expect("test symbol not found");
+
+        assert_eq!(
+            fn_symbol.description.as_ref().map(|d| d.as_ref()),
+            Some("function documentation")
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn test_syscall_documentation() -> Result<()> {
+        let metadata = compile!(metadata "fn test() { clr(d0); }");
+
+        let clr_symbol = metadata
+            .symbols
+            .iter()
+            .find(|s| s.name == "clr")
+            .expect("clr syscall not found");
+
+        // clr should have its built-in documentation
+        assert!(clr_symbol.description.is_some());
+        assert!(!clr_symbol.description.as_ref().unwrap().is_empty());
+        Ok(())
+    }
+
+    #[test]
+    fn test_variable_references_have_tooltips() -> Result<()> {
+        let metadata = compile!(metadata "/// documented variable\nlet myVar = 5;\nlet x = myVar + 2;\nmyVar = 10;");
+
+        // Count how many times 'myVar' appears in symbols
+        let myvar_symbols: Vec<_> = metadata
+            .symbols
+            .iter()
+            .filter(|s| s.name == "myVar")
+            .collect();
+
+        // We should have at least 2: declaration + 1 reference (in myVar + 2)
+        // The assignment `myVar = 10` is a write, not a read, so doesn't create a reference
+        assert!(
+            myvar_symbols.len() >= 2,
+            "Expected at least 2 'myVar' symbols (declaration + reference), got {}",
+            myvar_symbols.len()
+        );
+
+        // All should have the same description
+        let expected_desc = "documented variable";
+        for sym in &myvar_symbols {
+            assert_eq!(
+                sym.description.as_ref().map(|d| d.as_ref()),
+                Some(expected_desc),
+                "Symbol description mismatch at {:?}",
+                sym.span
+            );
+        }
+        Ok(())
+    }
+}
--- a/rust_compiler/libs/compiler/src/v1.rs
+++ b/rust_compiler/libs/compiler/src/v1.rs
@@ -145,6 +145,7 @@ struct CompileLocation<'a> {
 pub struct CompilationResult<'a> {
    pub errors: Vec<Error<'a>>,
    pub instructions: Instructions<'a>,
+    pub metadata: crate::CompilationMetadata<'a>,
 }

 /// Metadata for the currently compiling function
@@ -202,6 +203,8 @@ pub struct Compiler<'a> {
    pub source_map: HashMap<usize, Vec<Span>>,
    /// Accumulative errors from the compilation process
    pub errors: Vec<Error<'a>>,
+    /// Metadata about symbols encountered during compilation
+    pub metadata: crate::CompilationMetadata<'a>,
 }

 impl<'a> Compiler<'a> {
@@ -219,6 +222,7 @@ impl<'a> Compiler<'a> {
            loop_stack: Vec::new(),
            source_map: HashMap::new(),
            errors: Vec::new(),
+            metadata: crate::CompilationMetadata::new(),
        }
    }

@@ -237,6 +241,7 @@ impl<'a> Compiler<'a> {
                return CompilationResult {
                    errors: self.errors,
                    instructions: self.instructions,
+                    metadata: self.metadata,
                };
            }
            Err(e) => {
@@ -245,6 +250,7 @@ impl<'a> Compiler<'a> {
                return CompilationResult {
                    errors: self.errors,
                    instructions: self.instructions,
+                    metadata: self.metadata,
                };
            }
        };
@@ -270,6 +276,7 @@ impl<'a> Compiler<'a> {
            return CompilationResult {
                errors: self.errors,
                instructions: self.instructions,
+                metadata: self.metadata,
            };
        }

@@ -283,6 +290,7 @@ impl<'a> Compiler<'a> {
        CompilationResult {
            errors: self.errors,
            instructions: self.instructions,
+            metadata: self.metadata,
        }
    }

@@ -457,10 +465,23 @@ impl<'a> Compiler<'a> {
            },
            Expression::Variable(name) => {
                match scope.get_location_of(&name.node, Some(name.span)) {
-                    Ok(loc) => Ok(Some(CompileLocation {
-                        location: loc,
-                        temp_name: None, // User variable, do not free
-                    })),
+                    Ok(loc) => {
+                        // Track this variable reference in metadata (for tooltips on all usages, not just declaration)
+                        let doc_comment: Option<Cow<'a, str>> = self
+                            .parser
+                            .get_declaration_doc(name.node.as_ref())
+                            .map(|s| Cow::Owned(s) as Cow<'a, str>);
+                        self.metadata.add_variable_with_doc(
+                            name.node.clone(),
+                            Some(name.span),
+                            doc_comment,
+                        );
+
+                        Ok(Some(CompileLocation {
+                            location: loc,
+                            temp_name: None, // User variable, do not free
+                        }))
+                    }
                    Err(_) => {
                        // fallback, check devices
                        if let Some(device) = self.devices.get(&name.node) {
@@ -644,6 +665,14 @@ impl<'a> Compiler<'a> {
        if let Expression::Variable(ref name) = expr.node
            && let Some(device_id) = self.devices.get(&name.node)
        {
+            // Track this device reference in metadata (for tooltips on all usages, not just declaration)
+            let doc_comment = self
+                .parser
+                .get_declaration_doc(name.node.as_ref())
+                .map(Cow::Owned);
+            self.metadata
+                .add_variable_with_doc(name.node.clone(), Some(expr.span), doc_comment);
+
            return Ok((Operand::Device(device_id.clone()), None));
        }

@@ -696,6 +725,14 @@ impl<'a> Compiler<'a> {
        let name_str = var_name.node;
        let name_span = var_name.span;

+        // Track the variable in metadata
+        let doc_comment = self
+            .parser
+            .get_declaration_doc(name_str.as_ref())
+            .map(Cow::Owned);
+        self.metadata
+            .add_variable_with_doc(name_str.clone(), Some(name_span), doc_comment);
+
        // optimization. Check for a negated numeric literal (including nested negations)
        // e.g., -5, -(-5), -(-(5)), etc.
        if let Some(num) = self.try_fold_negation(&expr.node) {
@@ -1055,6 +1092,17 @@ impl<'a> Compiler<'a> {
            value: const_value,
        } = expr;

+        // Track the const variable in metadata
+        let doc_comment = self
+            .parser
+            .get_declaration_doc(const_name.node.as_ref())
+            .map(Cow::Owned);
+        self.metadata.add_variable_with_doc(
+            const_name.node.clone(),
+            Some(const_name.span),
+            doc_comment,
+        );
+
        // check for a hash expression or a literal
        let value = match const_value {
            LiteralOr::Or(Spanned {
@@ -1478,6 +1526,29 @@ impl<'a> Compiler<'a> {
    ) -> Result<(), Error<'a>> {
        let TupleDeclarationExpression { names, value } = tuple_decl;

+        // Track each variable in the tuple declaration
+        // Get doc for the first variable
+        let first_var_name = names
+            .iter()
+            .find(|n| n.node.as_ref() != "_")
+            .map(|n| n.node.to_string());
+        let doc_comment = first_var_name
+            .as_ref()
+            .and_then(|name| self.parser.get_declaration_doc(name))
+            .map(Cow::Owned);
+
+        for (i, name_spanned) in names.iter().enumerate() {
+            if name_spanned.node.as_ref() != "_" {
+                // Only attach doc comment to the first variable
+                let comment = if i == 0 { doc_comment.clone() } else { None };
+                self.metadata.add_variable_with_doc(
+                    name_spanned.node.clone(),
+                    Some(name_spanned.span),
+                    comment,
+                );
+            }
+        }
+
        match value.node {
            Expression::Invocation(invoke_expr) => {
                // Execute the function call - tuple values will be on the stack
@@ -1916,6 +1987,17 @@ impl<'a> Compiler<'a> {
        &mut self,
        expr: DeviceDeclarationExpression<'a>,
    ) -> Result<(), Error<'a>> {
+        // Track the device declaration in metadata
+        let doc_comment = self
+            .parser
+            .get_declaration_doc(expr.name.node.as_ref())
+            .map(Cow::Owned);
+        self.metadata.add_variable_with_doc(
+            expr.name.node.clone(),
+            Some(expr.name.span),
+            doc_comment,
+        );
+
        if self.devices.contains_key(&expr.name.node) {
            self.errors.push(Error::DuplicateIdentifier(
                expr.name.node.clone(),
@@ -2920,6 +3002,17 @@ impl<'a> Compiler<'a> {
        span: Span,
        scope: &mut VariableScope<'a, '_>,
    ) -> Result<Option<CompileLocation<'a>>, Error<'a>> {
+        // Track the syscall in metadata
+        let syscall_name = expr.name();
+        let doc = expr.docs().into();
+        self.metadata.add_syscall_with_doc(
+            Cow::Borrowed(syscall_name),
+            crate::SyscallType::System,
+            expr.arg_count(),
+            Some(span),
+            Some(doc),
+        );
+
        macro_rules! cleanup {
            ($($to_clean:expr),*) => {
                $(
@@ -3317,6 +3410,17 @@ impl<'a> Compiler<'a> {
        span: Span,
        scope: &mut VariableScope<'a, '_>,
    ) -> Result<Option<CompileLocation<'a>>, Error<'a>> {
+        // Track the syscall in metadata
+        let syscall_name = expr.name();
+        let doc = expr.docs().into();
+        self.metadata.add_syscall_with_doc(
+            Cow::Borrowed(syscall_name),
+            crate::SyscallType::Math,
+            expr.arg_count(),
+            Some(span),
+            Some(doc),
+        );
+
        macro_rules! cleanup {
            ($($to_clean:expr),*) => {
                $(
@@ -3577,6 +3681,19 @@ impl<'a> Compiler<'a> {

        let span = expr.span;

+        // Track the function definition in metadata
+        let param_names: Vec<Cow<'a, str>> = arguments.iter().map(|a| a.node.clone()).collect();
+        let doc_comment = self
+            .parser
+            .get_declaration_doc(name.node.as_ref())
+            .map(Cow::Owned);
+        self.metadata.add_function_with_doc(
+            name.node.clone(),
+            param_names,
+            Some(name.span),
+            doc_comment,
+        );
+
        if self.function_meta.locations.contains_key(&name.node) {
            self.errors
                .push(Error::DuplicateIdentifier(name.node.clone(), name.span));
--- a/rust_compiler/libs/parser/src/lib.rs
+++ b/rust_compiler/libs/parser/src/lib.rs
@@ -117,6 +117,10 @@ pub struct Parser<'a> {
    current_token: Option<Token<'a>>,
    last_token_span: Option<Span>,
    pub errors: Vec<Error<'a>>,
+    /// Caches the most recent doc comment for attaching to the next declaration
+    cached_doc_comment: Option<String>,
+    /// Maps variable/declaration names to their doc comments
+    pub declaration_docs: std::collections::HashMap<String, String>,
 }

 impl<'a> Parser<'a> {
@@ -126,6 +130,8 @@ impl<'a> Parser<'a> {
            current_token: None,
            last_token_span: None,
            errors: Vec::new(),
+            cached_doc_comment: None,
+            declaration_docs: std::collections::HashMap::new(),
        }
    }

@@ -151,6 +157,26 @@ impl<'a> Parser<'a> {
            })
    }

+    /// Pops and returns the cached doc comment, if any
+    pub fn pop_doc_comment(&mut self) -> Option<String> {
+        self.cached_doc_comment.take()
+    }
+
+    /// Caches a doc comment for attachment to the next declaration
+    pub fn cache_doc_comment(&mut self, comment: String) {
+        self.cached_doc_comment = Some(comment);
+    }
+
+    /// Stores a doc comment for a declaration (by name)
+    pub fn store_declaration_doc(&mut self, name: String, doc: String) {
+        self.declaration_docs.insert(name, doc);
+    }
+
+    /// Retrieves and removes a doc comment for a declaration
+    pub fn get_declaration_doc(&mut self, name: &str) -> Option<String> {
+        self.declaration_docs.get(name).cloned()
+    }
+
    fn unexpected_eof(&self) -> Error<'a> {
        Error::UnexpectedEOF(self.last_token_span)
    }
@@ -288,7 +314,36 @@ impl<'a> Parser<'a> {
        if let Some(token) = &self.current_token {
            self.last_token_span = Some(Self::token_to_span(token));
        }
-        self.current_token = self.tokenizer.next_token()?;
+
+        // Keep reading tokens, caching doc comments and skipping them
+        loop {
+            self.current_token = self.tokenizer.next_token_with_comments()?;
+
+            match &self.current_token {
+                Some(token) => {
+                    if let TokenType::Comment(comment) = &token.token_type {
+                        // Cache doc comments for attachment to the next declaration
+                        if let tokenizer::token::Comment::Doc(doc_text) = comment {
+                            self.cache_doc_comment(doc_text.to_string());
+                        }
+                        // Skip all comments (both doc and regular)
+                        continue;
+                    }
+
+                    // If we have a cached doc comment and encounter an identifier, associate them
+                    if let TokenType::Identifier(ref id) = token.token_type {
+                        if let Some(doc) = self.cached_doc_comment.take() {
+                            self.store_declaration_doc(id.to_string(), doc);
+                        }
+                    }
+
+                    // Non-comment token, use it as current
+                    break;
+                }
+                None => break, // EOF
+            }
+        }
+
        Ok(())
    }

@@ -511,7 +566,6 @@ impl<'a> Parser<'a> {

            TokenType::Keyword(Keyword::Const) => {
                let spanned_const = self.spanned(|p| p.const_declaration())?;
-
                Some(Spanned {
                    span: spanned_const.span,
                    node: Expression::ConstDeclaration(spanned_const),
--- a/rust_compiler/libs/parser/src/sys_call.rs
+++ b/rust_compiler/libs/parser/src/sys_call.rs
@@ -127,6 +127,52 @@ impl<'a> std::fmt::Display for Math<'a> {
    }
 }

+impl<'a> Math<'a> {
+    /// Returns the name of this math function (e.g., "acos", "sin", "sqrt", etc.)
+    pub fn name(&self) -> &'static str {
+        match self {
+            Math::Acos(_) => "acos",
+            Math::Asin(_) => "asin",
+            Math::Atan(_) => "atan",
+            Math::Atan2(_, _) => "atan2",
+            Math::Abs(_) => "abs",
+            Math::Ceil(_) => "ceil",
+            Math::Cos(_) => "cos",
+            Math::Floor(_) => "floor",
+            Math::Log(_) => "log",
+            Math::Max(_, _) => "max",
+            Math::Min(_, _) => "min",
+            Math::Rand => "rand",
+            Math::Sin(_) => "sin",
+            Math::Sqrt(_) => "sqrt",
+            Math::Tan(_) => "tan",
+            Math::Trunc(_) => "trunc",
+        }
+    }
+
+    /// Returns the number of arguments this math function expects
+    pub fn arg_count(&self) -> usize {
+        match self {
+            Math::Acos(_) => 1,
+            Math::Asin(_) => 1,
+            Math::Atan(_) => 1,
+            Math::Atan2(_, _) => 2,
+            Math::Abs(_) => 1,
+            Math::Ceil(_) => 1,
+            Math::Cos(_) => 1,
+            Math::Floor(_) => 1,
+            Math::Log(_) => 1,
+            Math::Max(_, _) => 2,
+            Math::Min(_, _) => 2,
+            Math::Rand => 0,
+            Math::Sin(_) => 1,
+            Math::Sqrt(_) => 1,
+            Math::Tan(_) => 1,
+            Math::Trunc(_) => 1,
+        }
+    }
+}
+
 documented! {
    #[derive(Debug, PartialEq, Eq)]
    pub enum System<'a> {
@@ -297,6 +343,48 @@ impl<'a> std::fmt::Display for System<'a> {
    }
 }

+impl<'a> System<'a> {
+    /// Returns the name of this syscall (e.g., "yield", "sleep", "hash", etc.)
+    pub fn name(&self) -> &'static str {
+        match self {
+            System::Yield => "yield",
+            System::Sleep(_) => "sleep",
+            System::Clr(_) => "clr",
+            System::Hash(_) => "hash",
+            System::LoadFromDevice(_, _) => "loadFromDevice",
+            System::LoadBatch(_, _, _) => "loadBatch",
+            System::LoadBatchNamed(_, _, _, _) => "loadBatchNamed",
+            System::SetOnDevice(_, _, _) => "setOnDevice",
+            System::SetOnDeviceBatched(_, _, _) => "setOnDeviceBatched",
+            System::SetOnDeviceBatchedNamed(_, _, _, _) => "setOnDeviceBatchedNamed",
+            System::LoadSlot(_, _, _) => "loadSlot",
+            System::SetSlot(_, _, _, _) => "setSlot",
+            System::LoadReagent(_, _, _) => "loadReagent",
+            System::Rmap(_, _) => "rmap",
+        }
+    }
+
+    /// Returns the number of arguments this syscall expects
+    pub fn arg_count(&self) -> usize {
+        match self {
+            System::Yield => 0,
+            System::Sleep(_) => 1,
+            System::Clr(_) => 1,
+            System::Hash(_) => 1,
+            System::LoadFromDevice(_, _) => 2,
+            System::LoadBatch(_, _, _) => 3,
+            System::LoadBatchNamed(_, _, _, _) => 4,
+            System::SetOnDevice(_, _, _) => 3,
+            System::SetOnDeviceBatched(_, _, _) => 3,
+            System::SetOnDeviceBatchedNamed(_, _, _, _) => 4,
+            System::LoadSlot(_, _, _) => 3,
+            System::SetSlot(_, _, _, _) => 4,
+            System::LoadReagent(_, _, _) => 3,
+            System::Rmap(_, _) => 2,
+        }
+    }
+}
+
 #[allow(clippy::large_enum_variant)]
 #[derive(Debug, PartialEq, Eq)]
 /// This represents built in functions that cannot be overwritten, but can be invoked by the user as functions.
--- a/rust_compiler/libs/tokenizer/src/lib.rs
+++ b/rust_compiler/libs/tokenizer/src/lib.rs
@@ -68,6 +68,12 @@ impl<'a> Tokenizer<'a> {

        Ok(current.map(|t| t.map(|t| self.get_token(t)))?)
    }
+
+    /// Returns the next token, including comments. Used to preserve doc comments.
+    pub fn next_token_with_comments(&mut self) -> Result<Option<Token<'a>>, Error> {
+        let current = self.lexer.next().transpose();
+        Ok(current.map(|t| t.map(|t| self.get_token(t)))?)
+    }
 }

 // ... Iterator and TokenizerBuffer implementations remain unchanged ...
@@ -127,12 +133,28 @@ impl<'a> TokenizerBuffer<'a> {
        self.index += 1;
        Ok(token)
    }
+
+    pub fn next_token_with_comments(&mut self) -> Result<Option<Token<'a>>, Error> {
+        if let Some(token) = self.buffer.pop_front() {
+            self.history.push_back(token.clone());
+            self.index += 1;
+            return Ok(Some(token));
+        }
+        let token = self.tokenizer.next_token_with_comments()?;
+
+        if let Some(ref token) = token {
+            self.history.push_back(token.clone());
+        }
+
+        self.index += 1;
+        Ok(token)
+    }
    pub fn peek(&mut self) -> Result<Option<Token<'a>>, Error> {
        if let Some(token) = self.buffer.front() {
            return Ok(Some(token.clone()));
        }

-        let Some(new_token) = self.tokenizer.next_token()? else {
+        let Some(new_token) = self.tokenizer.next_token_with_comments()? else {
            return Ok(None);
        };
        self.buffer.push_front(new_token.clone());
--- a/rust_compiler/src/ffi/mod.rs
+++ b/rust_compiler/src/ffi/mod.rs
@@ -94,6 +94,30 @@ impl From<lsp_types::Diagnostic> for FfiDiagnostic {
    }
 }

+#[derive_ReprC]
+#[repr(C)]
+pub struct FfiSymbolKindData {
+    pub kind: u32, // 0=Function, 1=Syscall, 2=Variable
+    pub arg_count: u32,
+    pub syscall_type: u32, // 0=System, 1=Math (only for Syscall kind)
+}
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct FfiSymbolInfo {
+    pub name: safer_ffi::String,
+    pub kind_data: FfiSymbolKindData,
+    pub span: FfiRange,
+    pub description: safer_ffi::String,
+}
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct FfiDiagnosticsAndSymbols {
+    pub diagnostics: safer_ffi::Vec<FfiDiagnostic>,
+    pub symbols: safer_ffi::Vec<FfiSymbolInfo>,
+}
+
 #[ffi_export]
 pub fn free_ffi_compilation_result(input: FfiCompilationResult) {
    drop(input)
@@ -109,6 +133,11 @@ pub fn free_ffi_diagnostic_vec(v: safer_ffi::Vec<FfiDiagnostic>) {
    drop(v)
 }

+#[ffi_export]
+pub fn free_ffi_diagnostics_and_symbols(v: FfiDiagnosticsAndSymbols) {
+    drop(v)
+}
+
 #[ffi_export]
 pub fn free_string(s: safer_ffi::String) {
    drop(s)
@@ -182,6 +211,10 @@ pub fn tokenize_line(input: safer_ffi::slice::Ref<'_, u16>) -> safer_ffi::Vec<Ff
        let input = String::from_utf16_lossy(input.as_slice());
        let tokenizer = Tokenizer::from(input.as_str());

+        // Build a lookup table for syscall documentation
+        let syscall_docs: std::collections::HashMap<&'static str, String> =
+            SysCall::get_all_documentation().into_iter().collect();
+
        let mut tokens = Vec::new();

        for token in tokenizer {
@@ -217,13 +250,26 @@ pub fn tokenize_line(input: safer_ffi::slice::Ref<'_, u16>) -> safer_ffi::Vec<Ff
                }
                Ok(Token {
                    span, token_type, ..
-                }) => tokens.push(FfiToken {
-                    column: span.start as i32,
-                    error: "".into(),
-                    length: (span.end - span.start) as i32,
-                    tooltip: token_type.docs().into(),
-                    token_kind: token_type.into(),
-                }),
+                }) => {
+                    let mut tooltip = token_type.docs();
+
+                    // If no docs from token type, check if it's a syscall
+                    if tooltip.is_empty() {
+                        if let TokenType::Identifier(id) = &token_type {
+                            if let Some(doc) = syscall_docs.get(id.as_ref()) {
+                                tooltip = doc.clone();
+                            }
+                        }
+                    }
+
+                    tokens.push(FfiToken {
+                        column: span.start as i32,
+                        error: "".into(),
+                        length: (span.end - span.start) as i32,
+                        tooltip: tooltip.into(),
+                        token_kind: token_type.into(),
+                    })
+                }
            }
        }

@@ -257,6 +303,88 @@ pub fn diagnose_source(input: safer_ffi::slice::Ref<'_, u16>) -> safer_ffi::Vec<
    res.unwrap_or(vec![].into())
 }

+#[ffi_export]
+pub fn diagnose_source_with_symbols(
+    input: safer_ffi::slice::Ref<'_, u16>,
+) -> FfiDiagnosticsAndSymbols {
+    let res = std::panic::catch_unwind(|| {
+        let input = String::from_utf16_lossy(input.as_slice());
+
+        let tokenizer = Tokenizer::from(input.as_str());
+        let compiler = Compiler::new(Parser::new(tokenizer), None);
+
+        let CompilationResult {
+            errors: diagnosis,
+            metadata,
+            ..
+        } = compiler.compile();
+
+        // Convert diagnostics
+        let mut diagnostics_vec: Vec<FfiDiagnostic> = Vec::with_capacity(diagnosis.len());
+        for err in diagnosis {
+            diagnostics_vec.push(lsp_types::Diagnostic::from(err).into());
+        }
+
+        // Convert symbols
+        let mut symbols_vec: Vec<FfiSymbolInfo> = Vec::with_capacity(metadata.symbols.len());
+        for symbol in &metadata.symbols {
+            let (kind, arg_count, syscall_type) = match &symbol.kind {
+                compiler::SymbolKind::Function { parameters, .. } => {
+                    (0, parameters.len() as u32, 0)
+                }
+                compiler::SymbolKind::Syscall {
+                    syscall_type,
+                    argument_count,
+                } => {
+                    let sc_type = match syscall_type {
+                        compiler::SyscallType::System => 0,
+                        compiler::SyscallType::Math => 1,
+                    };
+                    (1, *argument_count as u32, sc_type)
+                }
+                compiler::SymbolKind::Variable { .. } => (2, 0, 0),
+            };
+
+            let span = symbol
+                .span
+                .as_ref()
+                .map(|s| (*s).into())
+                .unwrap_or(FfiRange {
+                    start_line: 0,
+                    end_line: 0,
+                    start_col: 0,
+                    end_col: 0,
+                });
+
+            symbols_vec.push(FfiSymbolInfo {
+                name: symbol.name.to_string().into(),
+                kind_data: FfiSymbolKindData {
+                    kind,
+                    arg_count,
+                    syscall_type,
+                },
+                span,
+                description: symbol
+                    .description
+                    .as_ref()
+                    .map(|d| d.to_string())
+                    .unwrap_or_default()
+                    .into(),
+            });
+        }
+
+        FfiDiagnosticsAndSymbols {
+            diagnostics: diagnostics_vec.into(),
+            symbols: symbols_vec.into(),
+        }
+    });
+
+    res.unwrap_or(FfiDiagnosticsAndSymbols {
+        diagnostics: vec![].into(),
+        symbols: vec![].into(),
+    })
+}
+
 #[ffi_export]
 pub fn get_docs() -> safer_ffi::Vec<FfiDocumentedItem> {
    let res = std::panic::catch_unwind(|| {
Author	SHA1	Message	Date
Devin Bidwell	b8521917b8	First pass getting user documentation in the IDE All checks were successful CI/CD Pipeline / test (pull_request) Successful in 38s Details CI/CD Pipeline / build (pull_request) Has been skipped Details CI/CD Pipeline / release (pull_request) Has been skipped Details	2026-01-02 19:14:58 -07:00
Devin Bidwell	4ff0ff1b66	Track various symbols in the parse stage of Slang	2026-01-02 17:06:43 -07:00
Devin Bidwell	6dc4342ac3	First pass getting deeper LSP into IDE	2026-01-02 16:57:06 -07:00