34bfabccbd
Issue #23 now covers function naming conventions, file organisation, global namespace cleanup options, and a concrete implementation plan.
38 lines
1.1 KiB
Markdown
38 lines
1.1 KiB
Markdown
# 05 — Implement environment variable access (read/write)
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**Status:** done
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**Blocked by:** #01
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Add syntax for reading and writing environment variables directly from Lua.
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## Option 1 — `export` keyword
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```lua
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local var = "my data"
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export var -- exports existing local to env
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export other_var = "my data" -- creates + exports
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```
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- New reserved word `export` in lexer
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- `export var` looks up the local's value by name and calls `setenv()`
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- `export x = val` combines declaration with `setenv()`
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## Option 2 — `$` sigil
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```lua
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local dir = $PWD -- getenv("PWD")
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$PWD = "/" -- setenv("PWD", "/")
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$MY_ENV_VAR = "data" -- setenv("MY_ENV_VAR", "data")
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```
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- `$NAME` as expression → `getenv("NAME")`, returns string or `nil`
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- `$NAME = expr` as statement → `setenv("NAME", tostring(expr))`
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- New token type in lexer for `$` + identifier
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## Implementation touches
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- `llex.c` / `llex.h` — new token(s) or reserved word
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- `lparser.c` — new expression/statement rules
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- Runtime calls `getenv()` / `setenv()` — standard C, no shell needed
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- Non-existent env var → return `nil`
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