RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 20:28:11 +00:00
Code Issues Activity Actions

Shell: Add support for enumerating lists in for loops

Browse source 
With some odd syntax to boot:
```sh
$ for index i x in $whatever {}
```
This commit is contained in:
AnotherTest 2021-03-05 18:25:09 +03:30 • committed by Andreas Kling
parent a45b2ea6fb
commit 13b65b632a
8 changed files with 133 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

12
Base/usr/share/man/man5/Shell.md
View file

@ -211,9 +211,12 @@ if A {
##### For Loops
For Loops evaluate a sequence of commands once per element in a given list.
The shell has two forms of _for loops_, one with an explicitly named iteration variable, and one with an implicitly named one.
The general syntax follows the form `for name in expr { sequence }`, and allows omitting the `name in` part to implicitly name the variable `it`.
The general syntax follows the form `for index index_name name in expr { sequence }`, and allows omitting the `index index_name name in` part to implicitly name the variable `it`.
A for-loop evaluates the _sequence_ once per every element in the _expr_, seetting the local variable _name_ to the element being processed.
It should be noted that the `index index_name` section is optional, but if supplied, will require an explicit iteration variable as well.
In other words, `for index i in foo` is not valid syntax.
A for-loop evaluates the _sequence_ once per every element in the _expr_, seetting the local variable _name_ to the element being processed, and the local variable _enum name_ to the enumeration index (if set).
The Shell shall cancel the for loop if two consecutive commands are interrupted via SIGINT (\^C), and any other terminating signal aborts the loop entirely.
@ -224,6 +227,9 @@ $ for * { mv $it 1-$it }
# Iterate over a sequence and write each element to a file
$ for i in $(seq 1 100) { echo $i >> foo }
# Iterate over some files and get their index
$ for index i x in * { echo file at index $i is named $x }
```
##### Infinite Loops
@ -365,7 +371,7 @@ control_structure[c] :: for_expr
continuation_control :: 'break'
| 'continue'
for_expr :: 'for' ws+ (identifier ' '+ 'in' ws*)? expression ws+ '{' [c] toplevel '}'
for_expr :: 'for' ws+ (('enum' ' '+ identifier)? identifier ' '+ 'in' ws*)? expression ws+ '{' [c] toplevel '}'
loop_expr :: 'loop' ws* '{' [c] toplevel '}'