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The Pascal you love, reimagined for the modern era.
Blaise is a next-generation Object Pascal compiler built from the ground up to eliminate decades of legacy baggage. It prioritizes developer productivity, memory safety, and high-performance execution.
The Object Pascal ecosystem has two options: Embarcadero Delphi (proprietary,
Windows-first) and Free Pascal (open source but carrying 30 years of accumulated
complexity — five language modes, five string types, and thousands of include files).
This compiler takes a different approach:
-
One language mode. No
{$mode}switches; no legacy dialect support. -
One string type. UTF-8 reference-counted string.
RawBytesfor binary data. -
One memory model. Automatic reference counting applies uniformly to
strings, classes, and interfaces. No manual/auto split betweenTObject
andTInterfacedObject;[Weak]breaks cycles.Freeis retained as a
synonym for immediate release. -
Clean interfaces. No COM GUIDs; interface dispatch via compile-time vtable mapping.
-
Reified generics. Monomorphization at compile time — no type erasure.
-
Modern build system. PasBuild with
project.xml; no makefiles. -
First-class debugger. OPDF is the default debug format; DWARF is not required.
-
Self-Hosting: Yes. Blaise currently bootstraps and recompiles itself with byte-for-byte exact matches.
-
Testing: 1200+ tests and growing (Test-Driven Development from day one).
-
Backends: Currently utilizing a QBE backend, with an LLVM backend in active development.
| Phase | Goal | Status |
|---|---|---|
|
1 |
Bootstrap pipeline — Hello World on Linux x86_64 via PasBuild |
Complete ✅ |
|
2 |
Type system — classes, records, ARC, exceptions |
Complete ✅ |
|
3 |
Generics + zero-GUID interfaces |
Complete ✅ |
|
4 |
OPDF debug info emission |
Complete ✅ |
|
5 |
Self-hosting + LLVM + Windows + macOS ARM64 |
In-Progress |
|
6 |
LSP + VS Code extension |
Planned |
|
7 |
Migration analyser for FPC/Delphi codebases |
Planned |
| Feature | Reason for removal |
|---|---|
|
|
Replaced by a single UTF-8 reference-counted |
|
|
Source of hard-to-diagnose symbol resolution bugs; breaks static analysis |
|
Old-style |
Use |
|
COM-style interface GUIDs |
Interface dispatch via compile-time vtable; GUIDs are unnecessary complexity |
|
Multiple language modes |
One dialect, maintained well, beats five dialects maintained poorly |
|
|
Replaced by a stream-based I/O RTL |
|
|
One unified class model under automatic reference counting; |
The core architecture is still being finalised, so the project is not yet
accepting code contributions. Feedback on language design, syntax choices, and
the future direction of Blaise is very welcome — please use the
Discussions tab on GitHub.
This project uses PasBuild’s multi-module layout. Each subdirectory with a
project.xml is an independent module; the root project.xml is the aggregator.
project.xml Root aggregator (packaging=pom) │ ├── compiler/ The compiler binary (packaging=application) │ ├── project.xml │ └── src/ │ ├── main/pascal/ uLexer, uParser, uAST, uCodeGenQBE, ... │ └── test/pascal/ FPTest test suite for compiler units │ ├── rtl/ Runtime library (packaging=library) │ ├── project.xml │ └── src/ │ ├── main/pascal/ System.pas, SysUtils.pas, Classes.pas, ... │ └── test/pascal/ FPTest test suite for RTL units │ ├── tools/ │ └── migration-analyser/ FPC/Delphi migration report tool (packaging=application) │ ├── project.xml depends on compiler module │ └── src/ │ ├── main/pascal/ │ └── test/pascal/ │ ├── vendor/qbe/ Vendored QBE backend source (pinned, built from source) └── docs/ Design documents and specifications
PasBuild compiles each module to its own target/ subdirectory. Build output is
never committed to the repository.
-
Free Pascal Compiler 3.2.2 or later (stable; 3.3.x development snapshots are not required)
-
A C compiler (
gccorclang) for building the vendored QBE backend -
GNU
ldorlld(Linux);ld(macOS)
PasBuild resolves the module dependency order automatically and compiles
rtl → compiler → tools/migration-analyser.
pasbuild compile -p debug # includes -g -gl -Criot -gh
pasbuild compile -p release # includes -O2 -CX -XX -Xs
pasbuild compile -m blaise-compiler
Once built, the compiler binary is at compiler/target/blaise.
# Compile a single file
compiler/target/blaise --source Hello.pas --output Hello
# Compile via project.xml
compiler/target/blaise --project project.xml --config debug --output myapp
# Emit QBE IR (useful for debugging the compiler itself)
compiler/target/blaise --source Hello.pas --emit-ir
Apache License v2.0 with Runtime Library Exception. See LICENSE.
Built with ❤️ for the Pascal community by Graeme.
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