Yis

Vala was the war. Yis is the spoils.

This repository contains:

• yis: the Yis language compiler, which generates C

Requirements

• GCC or Clang with C11 support and GNU extensions (statement expressions, cleanup attributes, and checked arithmetic builtins)
• Meson
• Ninja
• Python 3 for the test suites and benchmarks

Example (macOS/Homebrew):

brew install meson ninja

Build Yis

meson setup build
meson compile -C build

Run the compiler from the build tree:

./build/yis --help
./build/yis examples/hello.yi
./build/yis run examples/hello.yi

Compile mode writes an executable in the current directory. run compiles into the binary cache and executes with the source directory as its working directory. Pass program arguments after --:

./build/yis run examples/hello.yi -- "argument with spaces"

Validation

Run the bootstrap, compiler, parser, optimizer, ownership, and native runtime regressions:

meson test -C build --print-errorlogs

Linux tests include AddressSanitizer and UndefinedBehaviorSanitizer checks for the native runtime. To run that harness separately:

python3 tests/test_runtime.py --sanitizers

Measure cold runs, cached runs, uncached compilation, and standalone runtime on bounded integer, array, and string workloads:

python3 tests/benchmark_compiler.py build/yis . --output /tmp/yis-benchmark.json

The JSON report includes timings, peak child-process RSS, and retained workload files. RSS can include the measurement worker's inherited memory at process startup. Compare repeated runs on the same machine; these workloads provide measurements without guaranteeing performance for other programs.

CI is configured for Ubuntu with GCC and Clang, and macOS with Clang. Validate the release commit's jobs before claiming support for those platforms. Windows has no CI coverage.

Optional Install

Install Yis and stdlib:

meson install -C build

Useful Environment Variables

Variable	Behavior
CC	C compiler executable or command with arguments; defaults to cc.
YIS_CC_FLAGS	Extra compiler/linker arguments appended after the defaults, such as -O2 -g.
YIS_STDLIB	Override the standard library directory.
YIS_CACHE_DIR	Override the run binary cache directory.
YIS_NO_CACHE=1	Force recompilation on run; compile mode always rebuilds.
YIS_KEEP_C=1	Keep generated .yis-c-* files in the output directory and force recompilation.
NO_COLOR=1	Disable colored bootstrap diagnostics.

The cache defaults to $XDG_CACHE_HOME/yis, or ~/.cache/yis, with .yi-cache as a fallback. Changes to source, transitive imports, runtime, compiler, or flags invalidate cached runs. Native-module programs and commands with untracked native inputs rebuild each time.

CC and YIS_CC_FLAGS accept quoted arguments and backslash escapes. Compile mode defaults to -Os; run defaults to -O1, which discards unused runtime helpers while keeping compilation fast. Override the optimization level when measuring runtime performance:

CC=clang YIS_CC_FLAGS="-O2" ./build/yis run examples/fizzbuzz.yi

Runtime behavior and limits

Integer arithmetic uses signed 64-bit values. Addition, subtraction, multiplication, and negation abort with runtime error: integer overflow on overflow. Integer division and remainder reject INT64_MIN / -1 and INT64_MIN % -1 with the same error. A zero divisor aborts with runtime error: division by zero. Floating-point arithmetic follows the C floating-point behavior. Integer literals must fit the signed 64-bit range. Float-to-integer conversion rejects nonfinite and out-of-range values; valid values truncate toward zero.

• Numeric values use tagged runtime representations; tight numeric loops can be substantially slower than equivalent primitive C loops.
• Heap values use reference counting. Cycles, such as an array containing itself, need to be broken explicitly to release their memory.
• Dictionary lookup and insertion scan entries linearly, so large dictionaries can be expensive.
• Repeated immutable string concatenation copies accumulated prefixes. Collect pieces and use stdr.join when building large strings.