Document that a for-loop passes through any exit status

Unlike in other shells, for-loops do not set $status if
1. the loop count is zero, or if
2. the loop body consists of only commands like "set" that don't
   set $status.

POSIX for-loops always set an exit status (they set 0 if no loop
iterations). Following that would be awkward because it would add a
lot of complexity in combination with the 2 special cases above.

Document that "for" behaves the same as "set": it will pass through
existing $status, and also the last child's $status.

See the discussion in #8409
This commit is contained in:
Johannes Altmanninger 2021-11-18 14:27:44 +01:00
parent 3c4969fc38
commit 0acbbfe2ca

View File

@ -15,6 +15,8 @@ Description
``for`` is a loop construct. It will perform the commands specified by ``COMMANDS`` multiple times. On each iteration, the local variable specified by ``VARNAME`` is assigned a new value from ``VALUES``. If ``VALUES`` is empty, ``COMMANDS`` will not be executed at all. The ``VARNAME`` is visible when the loop terminates and will contain the last value assigned to it. If ``VARNAME`` does not already exist it will be set in the local scope. For our purposes if the ``for`` block is inside a function there must be a local variable with the same name. If the ``for`` block is not nested inside a function then global and universal variables of the same name will be used if they exist. ``for`` is a loop construct. It will perform the commands specified by ``COMMANDS`` multiple times. On each iteration, the local variable specified by ``VARNAME`` is assigned a new value from ``VALUES``. If ``VALUES`` is empty, ``COMMANDS`` will not be executed at all. The ``VARNAME`` is visible when the loop terminates and will contain the last value assigned to it. If ``VARNAME`` does not already exist it will be set in the local scope. For our purposes if the ``for`` block is inside a function there must be a local variable with the same name. If the ``for`` block is not nested inside a function then global and universal variables of the same name will be used if they exist.
Much like :ref:`set <cmd-set>`, ``for`` does not modify $status, but the evaluation of its subordinate commands can.
Example Example
------- -------