tree-sitter-delphi13

Tree-sitter grammar pipeline focused on Delphi 13 (RAD Studio 37.0 / Florence) and the surrounding modern Delphi ecosystem.

v1.2.2: 100.000% pass rate on compilable Delphi 13 (zero ERROR nodes), measured on a corpus spanning the RAD Studio 13 RTL/VCL (including System.pas), DevExpress, Spring4D, EurekaLog, Indy, FireDAC, AsyncPro/Orpheus, JCL/JVCL (JEDI), mORMot-era community code and a full production application — 23,385 deduplicated files. Every failure that remains is individually diagnosed, dcc32-cross-checked, and supposed to fail (see CORPUS-CEILING-REPORT.md).

v1.2.2 added the JEDI (JCL + JVCL) libraries to the corpus and closed the three valid-Delphi-13 gaps they surfaced: a subrange bound that is a nested constant-expr call (2..Succ(High(T))), the at soft keyword as an inherited method name (inherited At(...)), and Operator used as a record/class field name.

| measurement basis | pass rate | |---|---| | orchestrated pipeline (preprocessor → pure), all rows | 99.82% | | deduplicated files | 99.74% | | deduplicated, valid-Delphi-13-only (excludes broken fixtures, FPC/.NET files) | 100.000% | | own production code (ORM3, drag-lint) | 100.00% |

The 30 files that still fail are intentionally broken test fixtures, truncated/corrupted files, FreePascal- or .NET-only sources, and vendor files with genuine syntax errors that dcc32 rejects too — a parser that accepted them would be wrong. Zero known gaps on valid Delphi 13 remain (TODO.md tracks the watchlist).

Three packages, one repo

| Package | What it does | |---|---| | tree-sitter-delphi13 (this directory) | Master grammar — Delphi-13 syntax, all proven fixes from upstream merged + new extensions. Self-contained "THEN-wins" parser (98.6% raw on its own). | | tree-sitter-delphi13-pure | Simpler sub-grammar that drops pp_* tokens entirely. Expects preprocessor-resolved source. | | delphi13-preprocessor | Standalone JavaScript library that resolves {$IFDEF} / {$IF} / {$DEFINE} / {$I X.inc} directives as a text transformation. The canonical preprocessor is now a pure-Delphi port of this library (shipping inside drag-lint); this JS package remains the byte-for-byte oracle and the drop-in choice for JavaScript consumers. |

The full pipeline preprocessor → pure → AST is what reaches 100.000% on valid Delphi 13. Use the master grammar alone (98.6% raw) if you don't need conditional-compilation awareness; use the pipeline if you do.

Architecture

raw .pas / .dpr / .dpk file
       │
       ▼
   delphi13-preprocessor      (text → text + source map)
   expands {$I X.inc} chains
   evaluates IFDEF expressions
   resolves per-project defines profiles
       │
       ▼
   tree-sitter-delphi13-pure  (text → AST)
   no pp_* tokens — simpler grammar
       │
       ▼
   AST

Splitting preprocessing from parsing was a 5+ percentage-point win over the best single-pass approach. The pattern is portable to any Pascal-family language with cpp-style conditional compilation.

Install

npm install tree-sitter-delphi13 tree-sitter

For the full preprocessor pipeline:

npm install tree-sitter-delphi13-pure delphi13-preprocessor tree-sitter

Quick start (master grammar)

const Parser = require('tree-sitter');
const Delphi13 = require('tree-sitter-delphi13');

const parser = new Parser();
parser.setLanguage(Delphi13);

const source = `
unit Hello;
interface
procedure SayHi;
implementation
procedure SayHi;
begin
  WriteLn('hi');
end;
end.
`;

const tree = parser.parse(source);
console.log(tree.rootNode.toString());

Quick start (preprocessor pipeline)

const fs = require('fs');
const Parser = require('tree-sitter');
const DelphiPure = require('tree-sitter-delphi13-pure');
const { preprocess } = require('delphi13-preprocessor');

const raw = fs.readFileSync('MyUnit.pas', 'utf8');

const { text } = preprocess(raw, {
  defines: ['MSWINDOWS', 'WIN64', 'CPU64BITS', 'UNICODE', 'COMPILER_VERSION_37'],
  numericDefines: { CompilerVersion: 37, RTLVersion: 37 },
  baseDir: 'C:/MyProject',
});

const parser = new Parser();
parser.setLanguage(DelphiPure);
const tree = parser.parse(text);

DFM companion

Delphi form files (.dfm / .fmx, text format) have their own grammar at tree-sitter-dfm — 100% on 11,044 real DFM files.

npm install tree-sitter-dfm

Build from source

git clone https://github.com/Alexl-git/tree-sitter-delphi13
cd tree-sitter-delphi13
npm install --ignore-scripts
./node_modules/.bin/tree-sitter generate
node-gyp rebuild

Known limitations

• Inline asm blocks treated as opaque text by design. Not tree-sitter-asm.
• {$IF declared(SymName)} always evaluates to false — no symbol table. ~10 corpus files use this. A lightweight symbol pre-scan would address most cases.
• Include resolution is nearest-first (same directory, its subdirectories, then up to 3 parent levels with their subdirectories — v1.1.0 of the preprocessor). Arbitrary project search paths still need the includePaths option.
• FreePascal-specific extensions (operator overloading variants, {$mode ObjFPC} directives, macOS PasCocoa namespaces) are not covered. A separate tree-sitter-delphi-plus-fp repo is planned.

Acknowledgements

Built on Isopod/tree-sitter-pascal (MIT, originally by Philip Zander). The MIT license header is preserved.

A separate effort is upstreaming the applicable grammar-only extensions (30 atomic commits — caret control-char ^X, dotted property read/write, generic constraints, trailing labels, subrange extensions, package files, and more) back to upstream so the broader Pascal community can benefit.

License

MIT — same as upstream tree-sitter-pascal.