1ac5b4ea42
Recipes may now have a final variadic parameter:
```make
foo bar+:
@echo {{bar}}
```
Variadic parameters accept one or more arguments, and expand to a string containing those arguments separated by spaces:
```sh
$ just foo a b c d e
a b c d e
```
I elected to accept one or more arguments instead of zero or more arguments since unexpectedly empty arguments can sometimes be dangerous.
```make
clean dir:
rm -rf {{dir}}/bin
```
If `dir` is empty in the above recipe, you'll delete `/bin`, which is probably not what was intended.
69 lines
1.6 KiB
Markdown
69 lines
1.6 KiB
Markdown
justfile grammar
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================
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Justfiles are processed by a mildly context-sensitive tokenizer
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and a recursive descent parser. The grammar is mostly LL(1),
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although an extra token of lookahead is used to distinguish between
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export assignments and recipes with parameters.
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tokens
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------
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```
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BACKTICK = `[^`\n\r]*`
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COLON = :
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COMMENT = #([^!].*)?$
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NEWLINE = \n|\r\n
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EQUALS = =
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INTERPOLATION_START = {{
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INTERPOLATION_END = }}
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NAME = [a-zA-Z_-][a-zA-Z0-9_-]*
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PLUS = +
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RAW_STRING = '[^'\r\n]*'
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STRING = "[^"]*" # also processes \n \r \t \" \\ escapes
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INDENT = emitted when indentation increases
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DEDENT = emitted when indentation decreases
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LINE = emitted before a recipe line
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TEXT = recipe text, only matches in a recipe body
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```
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grammar
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-------
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```
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justfile : item* EOF
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item : recipe
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| assignment
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| export
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| eol
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eol : NEWLINE
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| COMMENT NEWLINE
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assignment : NAME '=' expression eol
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export : 'export' assignment
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expression : STRING
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| RAW_STRING
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| NAME
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| BACKTICK
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| expression '+' expression
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recipe : '@'? NAME parameter* ('+' parameter)? ':' dependencies? body?
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parameter : NAME
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| NAME '=' STRING
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| NAME '=' RAW_STRING
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dependencies : NAME+
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body : INDENT line+ DEDENT
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line : LINE (TEXT | interpolation)+ NEWLINE
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| NEWLINE
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interpolation : '{{' expression '}}'
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```
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