RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-27 00:47:45 +00:00
Code Issues Activity Actions

Shell: Document the new 'pattern as (list of names)' match syntax

Browse source
This commit is contained in:
AnotherTest 2020-10-28 18:41:44 +03:30 • committed by Andreas Kling
parent 1a4ac3531f
commit 3fa0b887ed
1 changed files with 14 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

16
Base/usr/share/man/man5/Shell.md
View file

@ -266,6 +266,7 @@ $ fn 1 2 3 4
The pattern matching construct `match` shall choose from a sequence of patterns, and execute the corresponding action in a new frame. The pattern matching construct `match` shall choose from a sequence of patterns, and execute the corresponding action in a new frame.
The choice is done by matching the result of the _matched expression_ (after expansion) against the _patterns_ (expanded down to either globs or literals). The choice is done by matching the result of the _matched expression_ (after expansion) against the _patterns_ (expanded down to either globs or literals).
Multiple _patterns_ can be attributed to a single given action by delimiting them with a pipe ('|') symbol. Multiple _patterns_ can be attributed to a single given action by delimiting them with a pipe ('|') symbol.
A _pattern_ (or the series of) may be annotated with an extra `as (...)` clause, which allows globbed parts of the matching pattern to be named and used in the matching block.
The expanded _matched expression_ can optionally be given a name using the `as name` clause after the _matched expression_, with which it may be accessible in the action clauses. The expanded _matched expression_ can optionally be given a name using the `as name` clause after the _matched expression_, with which it may be accessible in the action clauses.
@ -277,10 +278,12 @@ match "$(make_some_value)" as value {
(say\ *) { echo "No, I will not $value" } (say\ *) { echo "No, I will not $value" }
} }
# Match the result of running 'make_some_value', cast to a string. # Match the result of running 'make_some_value', cast to a string
# Note the `as (expr)` in the second pattern, which assigns whatever the `*` matches
# to the name `expr` inside the block.
match "$(make_some_value)" { match "$(make_some_value)" {
hello* { echo "Hi!" } hello* { echo "Hi!" }
say\ * { echo "No, I will not!" } say\ * as (expr) { echo "No, I will not say $expr!" }
} }
``` ```
@ -318,6 +321,7 @@ pipe_sequence :: command '|' pipe_sequence
control_structure :: for_expr control_structure :: for_expr
| if_expr | if_expr
| subshell | subshell
| match_expr
for_expr :: 'for' ws+ (identifier ' '+ 'in' ws*)? expression ws+ '{' toplevel '}' for_expr :: 'for' ws+ (identifier ' '+ 'in' ws*)? expression ws+ '{' toplevel '}'
@ -328,6 +332,14 @@ else_clause :: else '{' toplevel '}'
subshell :: '{' toplevel '}' subshell :: '{' toplevel '}'
match_expr :: 'match' ws+ expression ws* ('as' ws+ identifier)? '{' match_entry* '}'
match_entry :: match_pattern ws* (as identifier_list)? '{' toplevel '}'
identifier_list :: '(' (identifier ws*)* ')'
match_pattern :: expression (ws* '|' ws* expression)*
command :: redirection command command :: redirection command
| list_expression command? | list_expression command?