$Post¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

$Post

is a global variable whose value, if set, is applied to every output expression after evaluation.

Examples (2)¶

Every input below was run against the current Mathilda build and its output recorded.

Applications (2)¶

In[1]:= $Post = Framed
Out[1]= Framed[Framed]

In[2]:= 2 + 2
Out[2]= Framed[4]

Implementation notes¶

A REPL session hook, not a builtin. Registered (docstring only, no default OwnValue) in repl_hooks_init (src/repl_hooks.c). In each REPL cycle repl.c calls repl_apply_post(result) on the evaluator's output; when an OwnValue is set the helper builds $Post[expr] and runs it through evaluate() via hook_call_eval. This happens after evaluation and before Out[n] is stored, so $Post can transform the visible result. Unset = identity.

Attributes: none registered.

References¶

Source: src/repl_hooks.c
Specification: docs/spec/builtins/control-flow.md

Notes & additional examples¶

Notes¶

$Post, if set, is applied to every output expression after evaluation. Here $Post = Framed wraps each result in Framed[...] (note the assignment's own echo is also wrapped). Unset by default, in which case results are shown unmodified.