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Diffstat (limited to 'Base/usr')
| -rw-r--r-- | Base/usr/share/man/man5/Shell.md | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/Base/usr/share/man/man5/Shell.md b/Base/usr/share/man/man5/Shell.md index 6819691e2e..5c299ce74e 100644 --- a/Base/usr/share/man/man5/Shell.md +++ b/Base/usr/share/man/man5/Shell.md @@ -220,6 +220,37 @@ $ { for * { te $it } }& $ disown ``` +##### Functions +A function is a user-defined entity that can be used as a simple command to execute a compound command, optionally with some parameters. +Such a function is defined via the syntax below: + +```sh +function_name(explicitly_named_arguments...) { compound_command } +``` + +The function is named `function_name`, and has some explicitly named arguments `explicitly_named_arguments...`, which *must* be supplied by the caller, failure to do so will cause the command to exit with status 1. + +The compound command shall be executed whenever the simple command `function_name` is executed. +This execution shall be performed in a new local frame. + +Additionally, should the simple command containing the function name be in a pipeline, or requested to be run in the background, this execution shall be moved to a subshell; naturally, in such a case any changes to the shell state (such as variables, aliases, etc) shall not be leaked to the parent shell process. + +The passed arguments shall be stored in the special variables `*` and `ARGV`, and the explicitly named arguments shall be set, in order, from the first passed argument onwards. + + +The exit status of a function simple command shall be the exit status of the last command executed within the command, or 0 if the function has no commands. +The declaration is *not* a command, and will not alter the exit status. + +###### Examples +```sh +fn(a b c) { + echo $a $b $c \( $* \) +} + +$ fn 1 2 3 4 +# 1 2 3 ( 1 2 3 4 ) +``` + ## Formal Grammar ### Shell Grammar @@ -229,8 +260,11 @@ toplevel :: sequence? sequence :: variable_decls? or_logical_sequence terminator sequence | variable_decls? or_logical_sequence '&' sequence | variable_decls? or_logical_sequence + | variable_decls? function_decl (terminator sequence)? | variable_decls? terminator sequence +function_decl :: identifier '(' (ws* identifier)* ')' ws* '{' toplevel '}' + or_logical_sequence :: and_logical_sequence '|' '|' and_logical_sequence | and_logical_sequence |