args-parser refactor

helpers/arg-parser/README.md

@@ -1,4 +1,84 @@
-# Argument parser for bash scripts
+# Argument parser for bash scripts v1.6
+
+## Usage
+
+```shell
+# 1. add these lines after shebang:
+
+__RAW_ARGS__=("$@")
+source args.sh
+
+# 2. read arguments as flags:
+
+arg a 1 flag_a
+echo "Flag -a has value '$flag_a'"
+echo "Flag -a has value '$(arg a 1)'"
+
+arg b 1 flag_b
+echo "Flag -b has value '$flag_b'"
+echo "Flag -b has value '$(arg b 1)'"
+
+arg c 1 flag_c
+echo "Flag -c has value '$flag_c'"
+echo "Flag -c has value '$(arg c 1)'"
+
+arg d 1 flag_d
+echo "Flag -d has value '$flag_d'"
+echo "Flag -d has value '$(arg d 1)'"
+
+argl flag1 1 flag_1
+echo "Flag --flag1 has value '$flag_1'"
+echo "Flag --flag1 has value '$(argl flag1 1)'"
+
+argl flag2 1 flag_2
+echo "Flag --flag2 has value '$flag_2'"
+echo "Flag --flag2 has value '$(argl flag2 1)'"
+
+# 3. and/or read arguments' values:
+
+arg a 0 arg_a
+echo "Arg -a has value '$arg_a'"
+echo "Arg -a has value '$(arg a 0)'"
+
+arg b 0 arg_b
+echo "Arg -b has value '$arg_b'"
+echo "Arg -b has value '$(arg b 0)'"
+
+argl arg1 0 arg_1
+echo "Arg --arg1 has value '$arg_1'"
+echo "Arg --arg1 has value '$(argl arg1 0)'"
+
+argl arg2 0 arg_2
+echo "Arg --arg2 has value '$arg_2'"
+echo "Arg --arg2 has value '$(argl arg2 0)'"
+```
+
+## How it works
+
+1. Short arguments can be specified contiguously or separately
+   and their order does not matter, but before each of them
+   (or the first of them) one leading dash must be specified.
+
+   > Valid combinations: `-a -b -c`, `-cba`, `-b -azc "value of z"`
+
+2. Short arguments can have values and if are - value must go
+   next to argument itself.
+   
+   > Valid combinations: `-ab avalue`, `-ba avalue`, `-a avalue -b`
+   
+3. Long arguments cannot be combined like short ones and each
+   of them must be specified separately with two leading dashes.
+   
+   > Valid combinations: `--foo --bar`, `--bar --foo`
+   
+4. Long arguments can have a value which must be specified after `=`.
+   
+   > Valid combinations: `--foo value --bar`, `--bar --foo=value`
+   
+5. If arg value may contain space then value must be "double-quoted".
+
+6. You can use arg() or argl() to check presence of any arg, no matter
+   if it has value or not.
 
 More info:
 * 🇷🇺 [axenov.dev/bash-args](https://axenov.dev/bash-args/)
@@ -7,8 +87,8 @@ More info:
 Tested in Ubuntu 20.04.2 LTS in:
 
 ```
-bash 5.0.17(1)-release (x86_64-pc-linux-gnu)
-zsh 5.8 (x86_64-ubuntu-linux-gnu)
+bash 5.0.17(1)-release (x86_64-pc-linux-gnu) and later
+zsh 5.8 (x86_64-ubuntu-linux-gnu) and later
 ```
 
 ## Version history
@@ -26,4 +106,6 @@ v1.4 - new function argn()
      - some text corrections
 v1.5 - arg(), grep_match(): fixed searching for -e argument
      - grep_match(): redirect output into /dev/null
+v1.6 - removed useless argn()
+     - arg() and argl() refactored and now support values with whitespaces
 ```