path: root/Doc
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authorBart Schaefer <schaefer@ipost.com>2021-04-18 13:58:09 -0700
committerBart Schaefer <schaefer@ipost.com>2021-04-18 13:58:09 -0700
commit82ff9f24f170eea7daa935fdaa09ab75a2f277ff (patch)
treecef3fef19fbe032466fcfbe50b7b6aa0878300a5 /Doc
parent56ccb4a975bc87dd10bbbd6a1cfc296d6e2203b4 (diff)
48560: add TYPESET_TO_UNSET option to remove initialization of parameters
Changes typeset such that ${newparam-notset} yields "notset" and "typeset -p newparam" does not show an assignment to the parameter. This is similar to the default behavior of bash and ksh, with minor differences in typeset output. Also add tests for some POSIX incompatibilities plus minor changes for test harness robustness.
Diffstat (limited to 'Doc')
3 files changed, 20 insertions, 1 deletions
diff --git a/Doc/Zsh/builtins.yo b/Doc/Zsh/builtins.yo
index a7afe42cf..61dc6986f 100644
--- a/Doc/Zsh/builtins.yo
+++ b/Doc/Zsh/builtins.yo
@@ -1872,7 +1872,11 @@ ifnzman(noderef(Local Parameters))\
retain their special attributes when made local.
For each var(name)tt(=)var(value) assignment, the parameter
-var(name) is set to var(value).
+var(name) is set to var(value). If the assignment is omitted and var(name)
+does em(not) refer to an existing parameter, a new parameter is intialized
+to empty string, zero, or empty array (as appropriate), em(unless) the
+shell option tt(TYPESET_TO_UNSET) is set. When that option is set,
+the parameter attributes are recorded but the parameter remains unset.
If the shell option tt(TYPESET_SILENT) is not set, for each remaining
var(name) that refers to a parameter that is already set, the name and
diff --git a/Doc/Zsh/options.yo b/Doc/Zsh/options.yo
index 714e8a1a1..6e862fae8 100644
--- a/Doc/Zsh/options.yo
+++ b/Doc/Zsh/options.yo
@@ -1942,6 +1942,16 @@ If the option is set, they will only be shown when parameters are selected
with the `tt(-m)' option. The option `tt(-p)' is available whether or not
the option is set.
+item(tt(TYPESET_TO_UNSET) <K> <S>)(
+When declaring a new parameter with any of the `tt(typeset)' family of
+related commands, the parameter remains unset unless and until a
+value is explicity assigned to it, either in the `tt(typeset)' command
+itself or as a later assignment statement.
diff --git a/Doc/Zsh/params.yo b/Doc/Zsh/params.yo
index 36c1ae4c2..a9044336f 100644
--- a/Doc/Zsh/params.yo
+++ b/Doc/Zsh/params.yo
@@ -393,6 +393,11 @@ is compared to the pattern, and the first matching key found is the
result. On failure substitutes the length of the array plus one, as
discussed under the description of `tt(r)', or the empty string for an
associative array.
+Note: Although `tt(i)' may be applied to a scalar substitution to find
+the offset of a substring, the results are likely to be misleading when
+searching within substitutions that yield an empty string, or when
+searching for the empty substring.
Like `tt(i)', but gives the index of the last match, or all possible