clean: trim .gitignore to project-relevant patterns, add CLAUDE.md

.gitignore

@@ -1,143 +1,51 @@
-# Prerequisites
-*.d
+# Build directories
+cmake-build-*/
+build/
 
 # Object files
 *.o
-*.ko
 *.obj
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+
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-# When using Gradle or Maven with auto-import, you should exclude module files,
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+# CMake generated
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+CMakeFiles/
+cmake_install.cmake
+Makefile
+CTestTestfile.cmake
+compile_commands.json

CLAUDE.md

@@ -0,0 +1,100 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project overview
+
+Trigger is a small POSIX shell written in C (C11), originally adapted from Brennan
+Baker's "Write a Shell in C" tutorial and built with CMake. It now supports quoting,
+pipelines, I/O redirection, and glob expansion on top of the tutorial's core loop.
+
+## Build, run, test
+
+Build:
+    cmake -B cmake-build-debug -S .
+    cmake --build cmake-build-debug
+
+Run the shell:
+    ./cmake-build-debug/shell
+
+Run the full test suite:
+    ./run_tests.sh
+    # equivalent to: cmake -B/--build, then `cd cmake-build-debug && ctest --output-on-failure`
+
+Run a single test module (CTest test names: InputTests, BuiltinsTests, ExecuteTests,
+PipelineTests, GlobTests):
+    cd cmake-build-debug && ctest -R PipelineTests --output-on-failure
+
+Or run a test binary directly, e.g.:
+    ./cmake-build-debug/test_pipeline
+
+Lint (also enforced in CI as a separate `lint` job, see below):
+    clang-format --dry-run --Werror $(find src include tests -name '*.c' -o -name '*.h')
+    cmake -B cmake-build-debug -S . -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+    clang-tidy -p cmake-build-debug -warnings-as-errors=* $(find src include -name '*.c')
+
+CI (`.github/workflows/ci.yml`) runs on every PR and push to `main` with two jobs:
+`build-and-test` (`./run_tests.sh`) and `lint` (clang-format + clang-tidy, both
+warnings-as-errors). Formatting follows `.clang-format` (LLVM base, 4-space indent,
+100 col limit); tidy checks are configured in `.clang-tidy`. A tag matching `v*.*.*`
+triggers `.github/workflows/release.yml`, which builds a Release binary and attaches
+it to a GitHub release.
+
+## Architecture
+
+Data flow: `src/main.c` runs `trigger_loop()`, a read → split → execute → free REPL
+loop. Each iteration reads a line, tokenizes it via `trigger_split_line_ex()`
+(which also produces a parallel `glob_eligible` array), and hands both to
+`trigger_execute()`.
+
+- **Input/lexer** (`src/input.c`, `src/utils/utils.c`): `trigger_read_line()` reads
+  a raw line via `getline`. `trigger_split_line_ex()` delegates to
+  `parse_line_with_quotes()` in `src/utils/utils.c`, a hand-written state-machine
+  tokenizer (`ParserState`: NORMAL / IN_SINGLE_QUOTE / IN_DOUBLE_QUOTE / ESCAPED)
+  that handles single/double/backslash quoting and grows token/array buffers
+  dynamically. This is the most complex and previously-buggy part of the codebase —
+  trace through `process_character()` in `utils.c` before touching quote-parsing
+  behavior. On unclosed quotes it returns `NULL` rather than crashing; callers must
+  handle that. Alongside each token, it fills a parallel `glob_eligible` int array:
+  a token is glob-ineligible if any part of it came from inside quotes or from a
+  backslash escape, so `echo "*.c"` and `echo \*.c` are never expanded even though
+  `echo *.c` is. Downstream code must keep `tokens[i]` and `glob_eligible[i]` in
+  lockstep — they're always the same length and freed/reallocated together.
+- **Glob expansion** (`src/glob.c`): `expand_globs()` runs after tokenizing and
+  before pipeline/operator parsing. It only expands tokens marked glob-eligible and
+  containing `*`, `?`, or `[`, using libc `glob()` with `GLOB_NOCHECK` (an unmatched
+  pattern is passed through literally, shell-style). It rebuilds both the argv and
+  glob_eligible arrays since one input token can expand to N output tokens.
+- **Executor** (`src/execute.c`): `trigger_execute()` expands globs first, then
+  scans the (glob-eligible-aware) token stream for `|`, `<`, `>`, `>>`. If any are
+  present as real operators (not inside quotes), it hands off to
+  `trigger_parse_pipeline()` / `trigger_execute_pipeline()` in `src/pipeline.c`.
+  Otherwise it checks `args[0]` against the builtins table directly and falls
+  through to `trigger_launch()` (fork() + execvp() + waitpid()) for external
+  commands. A bare command with no operators never touches pipeline.c.
+- **Pipelines & redirection** (`src/pipeline.c`): `trigger_parse_pipeline()` splits
+  the token stream on `|` into `PipelineStage` structs (`argv`, `infile`, `outfile`,
+  `append`), consuming `<`/`>`/`>>` and their filename arguments out of each stage's
+  argv. `trigger_execute_pipeline()` has a fast path for a single stage with no
+  redirection (checks builtins, else `trigger_launch()`), a path for a single
+  builtin stage *with* redirection (saves/restores fds 0/1 around the builtin call
+  via `dup`/`dup2` since builtins run in-process), and a general N-stage path that
+  forks one child per stage, wires up `pipe()` fds between adjacent stages, and
+  waits on all children. In the N-stage path, builtins run inside the forked child
+  and `exit()` immediately after — only the single-stage paths run a builtin
+  in-process without forking.
+- **Builtins** (`src/builtins.c`): dispatch is two parallel arrays kept in lockstep
+  by hand — `builtin_str[]` (names: cd, help, exit, pwd, echo, export, unset) and
+  `builtin_func[]` (matching function pointers), iterated together by index in
+  `trigger_execute()`, `trigger_execute_pipeline()`, and `trigger_help()`. Adding a
+  builtin means appending to *both* arrays in the same position — there's no
+  struct/table enforcing this, so mismatches are easy to introduce.
+
+Headers in `include/` mirror `src/` (`input.h`, `execute.h`, `builtins.h`,
+`pipeline.h`, `glob_expand.h`), except `utils/utils.h`, which lives next to its
+`.c` file in `src/utils/` rather than in `include/`.
+
+Tests in `tests/` are per-module (`test_input.c`, `test_builtins.c`,
+`test_execute.c`, `test_pipeline.c`, `test_glob.c`) and link directly against the
+relevant `.c` files rather than a shared static library, using a small custom
+assertion framework in `tests/test_framework.h` (no external test dependency).