Support for regex and =~ operator

[KBeDevel]

Bash example:

line=" aaaaaab"

pattern="[[:space:]]*(a)?b"

if [[ $line =~ $pattern ]]; then
  echo "Matches"
fi

Source: https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html#Conditional-Constructs

Is there a way or plan to implement this with Amber?

The following code:

main (args) {
  let line = " aaaaaab"

  let pattern = "[[:space:]]*(a)?b"

  if line =~ pattern {
    echo "Matches"
  }
}

Does not compile:

 ERROR 
Identifier 'if' is a reserved keyword
at example.ab:6:3


5| 
6|   if text =~ pattern {
7|     echo "Matches"

Using Amber 0.3.3-alpha

[b1ek]

that's not an feature that is amber's responsibility to implement.

bash's if works like this:

if (command with args); then
    echo the command's exit code was 0;
fi

therefore if [[ ... ]] is not a bash thing. [[ is a command that is usually installed and behaves mostly the same between platforms.

to do this in amber correctly, you need to do this:

if unsafe $[[ "a" ~= "\w" ]]$ {
    echo "a is a letter"
}

[b1ek]

[[ probably should be added as a builtin tho. but that should be discussed in the issue about builtins

[Ph0enixKM]

We could add Regex to standard library

[Mte90]

A line of code:

if unsafe $[[ {packed_file} ~= ".tar." ]]$ {

Generate:

__AMBER_VAL_2=$([[ ${packed_file} ~= ".tar." ]]);

That fails in bash

[Mte90]

This is right:

 if $[[ {packed_file} = *".tar."* ]]$ {

that generates:

__AMBER_VAL_2=$([[ ${packed_file} = *".tar."* ]]);

The problem is that doens't return anything so the check is always true.

Instead should generate a code like:

if [[ ${packed_file} = *".tar."* ]]; then

In this way works

[Mte90]

I suggest for regex to use grep that works everywhere and will avoid the situation I mentioned.

[Mte90]

I am not sure if #453 fix this ticket as is a stdlib implementation