punkshell - an alternative Tcl Shell

BSD license

2023-08 Note: this is alpha level software and still highly experimental.

Features

• default ansi color output - toggle with 'colour on' and 'colour off'

• experimental functional/pattern-matching language features. (will not be performant until more work is done on script compilation)
  e.g.1 basic pipeline with 2 segments
  var_pipe_output.= var_list.= list a b c |> string toupper
  e.g.2 basic pattern-match multi-assignment to variables x y & z
  x@0,y@1,z@2.= list a b c equivalently: x@,y@,z@.= list a b c or even x@,y@,z@= {a b c}
x/0,y/1,z/2,zz/3.= list a b c is similar - but the use of forward-slash instead of @ will not produce a mismatch if an index is out of range.
  where .= indicates following arguments form a command, and a plain = accepts only a single argument as a value
  The diminutive case of this is x= "something" as equivalent to set x "something"
  Assignment operations and pattern-matches are slightly optimised to bytecompile, but are unlikely to compete with raw Tcl commands performance-wise.
  e.g.3 destructuring pattern-match. Get value of key 'k1' from last item in a list of dicts.
  x@end/@@k1.= list {k1 aaa} {k1 bb} returns bbb

  There are many more pattern-matching features yet to be documented.

• easy execution of externals commands with return of stdout, stderr and the exitcode of the process

  • run <comand> ...
    (return exitcode of process - and allows process writes to stderr/stdout to appear in console as they occur)
  • runout <command> ...
    (return stdout of process - no output until completion)
  • runerr <command> ...
    (return stderr of process - no output until completion)
  • runx <command> ... (return a dict of stdout stderr exitcode - no output until completion)

• namespace browser (contextual - allowing running of commands within the active namespace - analogous to 'cd' for directories)

  • n/ - display child namespaces of current namespace (alias :/)
    also n/ <globpattern> to restrict output
  • n/ <childns> - if the argument doesn't contain glob chars '*' or '?' - attempt to switch to a child namespace of that name. Analogous to cd <dir>
    list any sub namespaces of the namespace we just switched to.
  • n// - display child namespaces and commands (alias ://)
    with colourised indication of type such as proc,alias,ensemble,imported,exported where possible.
    (renamed aliases and builtins and commands loaded from binaries will appear unmarked)
  • nn/ - move up one namespace towards root namespace '::' analogous to cd .. (alias ::/)
  • n/new <somename> - create a child namespace called 'somename' and switch to it in one operation. (alias :/new)

• cross-platform alternative to cd & ls/dir without invoking child processes. Display colourised listing of dirs and folders - with vfs indication.

  • d/ - list current directory (alias ./)
    also d/ <globpattern> to restrict output
  • d/ <subdir> - switch to subdir and list contents in one operation
  • dd/ - move up one directory and output listing. Roughly equivalent to cd .. followed by dir or ls (alias ../)
  • d/new <folder> - create a child directory and switch to it in one operation. (alias ./new <folder>)

missing

• raw mode REPL (read-eval-print-loop) to allow commandline completion etc. Initial version is linemode. (intention is to allow different REPLs to be plugged)
• documentation!
• tests

very unripe parts:

• commandline options - in need of urgent work to document and lock down specifics - in particular: punkshell somescript.tcl needs a fix to emit errors.
• shellfilter - api is clumsy
• scriptlib - will likely be reorganised/pruned significantly