Workspaces and Namespaces¶

As your MARPLE code grows, you need ways to organise it. Workspaces save and load your session. Namespaces group functions into directories. The standard library ($:) provides built-in utilities.

Workspaces¶

A workspace is a snapshot of your defined functions and variables.

Saving and loading¶

      )wsid myproject          ⍝ name the workspace
      )save                    ⍝ save to disk
      )load myproject          ⍝ load it back
      )lib                     ⍝ list available workspaces

Workspaces are saved as directories containing .apl files — one per function. This means they're plain text, version-controllable, and easy to inspect.

Managing the workspace¶

      )fns                     ⍝ list all functions
      )vars                    ⍝ list all variables
      )clear                   ⍝ remove everything

Namespaces¶

A namespace is a subdirectory within a workspace. Functions in the utils/ subdirectory belong to the utils namespace.

Directory structure¶

myproject/
  main.apl              ⍝ top-level function
  utils/
    trim.apl            ⍝ utils:trim
    pad.apl             ⍝ utils:pad
  math/
    stats/
      mean.apl          ⍝ math:stats:mean

Calling namespaced functions¶

Use colon-separated qualified names:

      utils:trim '  hello  '
      math:stats:mean data

Why colon, not dot?

The dot (.) is APL's inner-product operator. foo.bar where foo and bar are functions is a legitimate inner product. The colon is unambiguous — it has no other infix meaning in APL.

Listing namespace contents¶

      )fns utils             ⍝ functions in the utils namespace
      )fns math:stats        ⍝ functions in math:stats

The standard library (`$:`)¶

MARPLE provides a built-in system workspace referenced by $. It contains utility functions organised into namespaces:

      $:io:nread '/tmp/data.txt'       ⍝ read a file
      $:str:trim '  hello  '           ⍝ trim whitespace
      $:error:ea                        ⍝ execute with error handling

$ is always available, regardless of your current workspace.

Available standard library namespaces¶

Namespace	Purpose
`$:io`	File I/O — `nread`, `nwrite`, `nexists`, `ndelete`
`$:str`	String utilities — `trim`, `split`, `join`, `upper`, `lower`, `u`, `v2m`
`$:sys`	System access — `argv`, `exit`, `env`
`$:error`	Error handling — `ea`, `en`

See the Standard Library Reference for full details.

Importing¶

To avoid typing full qualified names, use #import:

      #import $:io:nread                ⍝ import as nread
      #import $:str:trim as strip       ⍝ import with alias
      #import $:str                     ⍝ import namespace — use as str:trim

Import directives work in the REPL and in .apl source files. They are not valid inside dfns — use qualified names there.

Key points¶

Workspaces save as directories of .apl files — one function per file
Namespaces map to subdirectories; use ns:fn to call
The standard library is at $: and is always available
#import brings names into scope with optional aliases
Colon (:) separates namespace levels, not dot

This concludes the intermediate tutorials. For task-specific guidance, see the How-To Guides. For complete specifications, see the Reference.