41b2095ed9
Redesign issue #10: bare-word commands now work in both scripts and the REPL via a parser-level heuristic (identifier + non-exception-list token → shell command). Add runtime fallback for string-arg syntax (echo "hello"), double-dash flag handling, and classification examples. Add issue #12 for path-based command execution (./script, /bin/ls, ~/bin/deploy). Add testes/lush/commands-interactive.lua as a design playground covering result table structure, exit codes, commands inside Lua blocks, _ behaviour, runtime fallback, Lua variable shadowing, and interleaved Lua/shell.
78 lines
3.1 KiB
Markdown
78 lines
3.1 KiB
Markdown
# Issue #12 — Path-based command execution
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**Status:** open
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**Related:** #10 (interactive command execution)
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## Problem
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Issue #10's parser heuristic detects bare-word commands when an **identifier** at statement position is followed by a non-exception-list token. This covers `ls -la`, `git status`, etc. — but not commands invoked by path, because the first token isn't an identifier:
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```
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./script/update -- first token is .
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../lua -- first token is .
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/bin/ls -- first token is /
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~/bin/deploy -- first token is ~
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```
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In standard Lua, none of these are valid statement starts, so claiming them for shell commands doesn't steal any Lua syntax.
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## Proposed heuristic
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Add parser rules for path-prefixed commands. When the parser sees one of these tokens at statement position, treat the rest of the line as a shell command:
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| First token(s) | Pattern | Example |
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|----------------|---------|---------|
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| `.` `/` | dot-slash | `./script.sh` |
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| `.` `.` `/` | dot-dot-slash | `../other/build` |
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| `/` | absolute path | `/bin/ls -la` |
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| `~` `/` | home-relative path | `~/bin/deploy` |
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### Detection
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- `.` at statement position → peek next token:
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- `/` on same line → path command (`./ ...`)
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- `.` on same line → peek again: `/` → path command (`../ ...`)
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- anything else → parse as Lua (`.` could be a concat operator fragment, though this isn't valid at statement start anyway)
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- `/` at statement position → path command (not valid Lua statement start)
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- `~` at statement position → peek next token:
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- `/` on same line → path command (`~/ ...`)
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- anything else → parse as Lua (`~` is bitwise NOT in Lua 5.4, though `~expr` as a bare statement is already a syntax error)
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### Argument capture
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Same as issue #10: once detected, extract the raw text of the entire line from the source buffer. Emit bytecode equivalent to `_ = __interactive("raw line text")`.
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## Examples
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```lua
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-- all of these run as shell commands
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./configure --prefix=/usr/local
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../build/lush test.lua
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/usr/bin/env python3 -c "print('hello')"
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~/bin/deploy staging
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-- check exit code like any other interactive command
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./run-tests
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if _.code ~= 0 then
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print("tests failed")
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end
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```
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## Non-conflicts with Lua
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- `/` at statement start: not valid Lua (`/` is division, needs a left operand)
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- `./` at statement start: `.` is concat, `/` is division — `./foo` as Lua would be `. / foo` (concat divided by foo), which needs a left operand. Not valid at statement start.
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- `../` at statement start: same reasoning, not valid
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- `~/` at statement start: `~` is bitwise NOT, `/` is division — `~/foo` as Lua would be `(~()) / foo`, which isn't valid at statement start as a bare expression statement
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## Open questions
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- Should `~` without `/` be supported? (e.g., `~user/bin/script` — tilde expansion for other users). Probably not initially.
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- Should bare `.` or `..` (without `/`) be treated as commands? In shells, `source` is sometimes aliased to `.`. Probably not — too ambiguous.
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## Files touched
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| File | Description |
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|------|-------------|
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| `lparser.c` | Add path-prefix detection alongside the identifier heuristic in statement parsing |
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