Add joinEnv and joinUrl string functions and 2 new system vars

[solvingj]

Add two new system variables which map directly to platform specific go constants:

• PATH_LIST_SEPARATOR -> os.PathListSeparator
• FILE_PATH_SEPARATOR -> os.PathSeparator

Add joinEnv string function which is sibling to joinPath:

• strings.Join(elem, string(os.PathListSeparator))

Add joinUrl string function which is sibling to joinPath:

• path.Join(elem...)

Add all to docs

closes #2406

[trulede]

@solvingj there are quite a few functions already in https://go-task.github.io/slim-sprig/ and perhaps its better to use those existing list functions (join, append, prepend) since that gives a better control over how such lists/strings are generated.

The PathSeparator and PathListSeparator are useful however I would suggest following the existing most-predominate naming convention:

• PathSeparator -> osPathSeparator (note also the absence of "file")
• PathListSeparator -> osPathListSeparator

since the allcaps just looks ODD.

Observation: this could also be done with a .env file, introducing these constants (and others). Perhaps this PR is more effort than value.

[solvingj]

Up to @pd93 and @andreynering I suppose.

[vmaerten]

Hello!
Sorry for the delay, we have been busy lately.

PATH_LIST_SEPARATOR / FILE_PATH_SEPARATOR does not work in the templating system.

If you take this Taskfile :

# https://taskfile.dev

version: '3'

tasks:
  default:
    cmds:
      - echo "{{.PATH_LIST_SEPARATOR}}"
      - echo "{{.FILE_PATH_SEPARATOR}}"

You will get this result:

For these variables, you need to define them in getSpecialVars inside compiler.go

[solvingj]

For these variables, you need to define them in getSpecialVars inside compiler.go

Ah, of course, moved...

[vmaerten]

@solvingj the lint is failing. Do you still want to work on it?

[solvingj]

Yah I can fix it tomorrow. Just to confirm, are you sure you want to merge it?