67 lines
1.9 KiB
JavaScript
67 lines
1.9 KiB
JavaScript
module.exports = grammar({
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name: 'nix_shell',
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rules: {
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// TODO: allow trailing whitespace on any line
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source_file: $ => seq($.first_line, repeat($.next_line)),
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first_line: $ => seq($._shebang_open, $._opt_ws, optional(seq($._env, $._ws)), $._nix_shell),
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next_line: $ => seq($._newline, choice(
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$.annotation_line,
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repeat(/./),
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)),
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annotation_line: $ => seq($._shebang_open, $._opt_ws, $._nix_shell, optional($.nix_shell_args)),
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// nix acts as if it actually just `exec`'s whichever line contains `#! nix-shell` in the style of `sh`'s `exec`.
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// so arguments can be quoted, invoke subshells, interpolate environment variables, etc.
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// the full scope cannot be covered, but the minimal scope here gets 99% of use cases.
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nix_shell_args: $ => repeat1(seq($._ws, $._nix_shell_arg)),
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_nix_shell_arg: $ => choice(
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seq('-i', $._opt_ws, $.interpreter),
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$.sh_arg,
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),
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interpreter: $ => $.sh_arg,
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sh_arg: $ => choice(
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$._sh_lit,
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$._sh_quote1,
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$._sh_quote2,
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),
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_sh_lit: $ => repeat1(choice(
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/[^ \\]/,
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seq('\\', /./),
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)),
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_sh_quote1: $ => seq(
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'\'',
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repeat(choice(
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/[^'\\]/,
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seq('\\', /./),
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)),
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'\'',
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),
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_sh_quote2: $ => seq(
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'"',
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repeat(choice(
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/[^"\\]/,
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seq('\\', /./),
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)),
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'"',
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),
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_shebang_open: $ => '#!',
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// TODO: env accepts flags like `-v` or `--unset=NAME` or `VAR=VALUE` before `nix-shell`,
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_env: $ => choice(
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'/usr/bin/env',
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'/bin/env',
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'env',
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),
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_nix_shell: $ => 'nix-shell',
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// N.B.: this accepts more than it needs to:
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// - shebang parser allows tab characters
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// - #!nix-shell directives do not support tabs
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// - wherever #!nix-shell directives allow whitespace, it's a *single* space -- never multiple
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_ws: $ => /[ \t]+/,
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_opt_ws: $ => /[ \t]*/,
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_newline: $ => '\n',
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}
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});
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