[PATCH] Add API wrapper to ${+_comps[...]}

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

I wonder if this is useful enough to be added?

From ed7cddd08d7e3bcf7d60349917ecc50461f50dd1 Mon Sep 17 00:00:00 2001
From: Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>
Date: Wed, 30 Sep 2015 17:41:55 +0000
Subject: [PATCH 1/2] compdef documentation: Move an example.

---
 Doc/Zsh/compsys.yo | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/Doc/Zsh/compsys.yo b/Doc/Zsh/compsys.yo
index d6b1803..955b300 100644
--- a/Doc/Zsh/compsys.yo
+++ b/Doc/Zsh/compsys.yo
@@ -455,6 +455,11 @@ xitem(tt(compdef -k) [ tt(-an) ] var(function style key-sequence) [ var(key-sequ
 item(tt(compdef -K) [ tt(-an) ] var(function name style key-seq) [ var(name style seq) ... ])(
 The first form defines the var(function) to call for completion in the
 given contexts as described for the tt(#compdef) tag above.
+For example,
+
+example(compdef _pids foo)
+
+uses the function tt(_pids) to complete process IDs for the command tt(foo).
 
 Alternatively, all the arguments may have the form
 `var(cmd)tt(=)var(service)'.  Here var(service) should already have been
@@ -513,13 +518,6 @@ autoloadable, equivalent to tt(autoload -U )var(function).
 )
 enditem()
 
-The function tt(compdef) can be used to associate existing completion
-functions with new commands.  For example,
-
-example(compdef _pids foo)
-
-uses the function tt(_pids) to complete process IDs for the command tt(foo).
-
 Note also the tt(_gnu_generic) function described below, which can be
 used to complete options for commands that understand the
 `tt(-)tt(-help)' option.
-- 
2.1.4

From a67963b2be0ad72b462996da93e89b734b68efa0 Mon Sep 17 00:00:00 2001
From: Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>
Date: Wed, 30 Sep 2015 17:53:42 +0000
Subject: [PATCH 2/2] Add 'compexists'.

---
 Completion/compinit |  5 +++++
 Doc/Zsh/compsys.yo  | 12 +++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Completion/compinit b/Completion/compinit
index 4b9a778..ac7e672 100644
--- a/Completion/compinit
+++ b/Completion/compinit
@@ -430,6 +430,11 @@ compdef() {
   fi
 }
 
+compexists() {
+  (( $# )) || return 2
+  (( $+_comps[$1] ))
+}
+
 # Now we automatically make the definition files autoloaded.
 
 typeset _i_wdirs _i_wfiles
diff --git a/Doc/Zsh/compsys.yo b/Doc/Zsh/compsys.yo
index 955b300..444b966 100644
--- a/Doc/Zsh/compsys.yo
+++ b/Doc/Zsh/compsys.yo
@@ -445,9 +445,9 @@ subsect(Functions)
 The following function is defined by tt(compinit) and may be called
 directly.
 
+startitem()
 findex(compdef)
 cindex(completion system, adding definitions)
-startitem()
 redef(SPACES)(0)(tt(ifztexi(NOTRANS(@ @ @ @ @ @ ))ifnztexi(      )))
 xitem(tt(compdef) [ tt(-ane) ] var(function name) ... [ tt(-){tt(p)|tt(P)} var(pattern) ... [ tt(-N) var(name) ...]])
 xitem(tt(compdef -d) var(name) ...)
@@ -516,6 +516,16 @@ underscore.
 Wherever applicable, the tt(-a) option makes the var(function)
 autoloadable, equivalent to tt(autoload -U )var(function).
 )
+findex(compexists)
+cindex(completion system, checking existence of definitions)
+item(tt(compexists) var(name))(
+This function checks whether the command var(name) has completion.
+The return value is tt(0) if var(name) has a completion and tt(1) if it
+doesn't.  If no var(name) was passed, return tt(2).
+
+Completions for var(name) can be defined with tt(compdef), e.g.,
+with tt(compdef name=)var(foo) or tt(compdef )var(_foo)tt( name).
+)
 enditem()
 
 Note also the tt(_gnu_generic) function described below, which can be
-- 
2.1.4