From 4c92ff2fa92b487414de4ebdd87dbbe453cd2fdc Mon Sep 17 00:00:00 2001
From: Ingo Karkat <swdev@ingo-karkat.de>
Date: Wed, 15 Aug 2018 14:14:56 +0200
Subject: [PATCH] Add ingo#regexp#deconstruct#RemoveMultis()

---
 autoload/ingo/regexp/deconstruct.vim           | 18 ++++++++++++++++++
 .../regexp/deconstruct/t1100-RemoveMultis.vim  | 11 +++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 tests/regexp/deconstruct/t1100-RemoveMultis.vim

diff --git a/autoload/ingo/regexp/deconstruct.vim b/autoload/ingo/regexp/deconstruct.vim
index 86dac8f..09aed45 100644
--- a/autoload/ingo/regexp/deconstruct.vim
+++ b/autoload/ingo/regexp/deconstruct.vim
@@ -27,6 +27,24 @@ function! ingo#regexp#deconstruct#RemovePositionAtoms( pattern )
     return substitute(a:pattern, '\%(\%(^\|[^\\]\)\%(\\\\\)*\\\)\@<!\%(\\\%([\^<>]\|_\^\|_\$\|%[\^$V#]\|%[<>]\?''.\|%[<>]\?\d\+[lcv]\)\|[\^$]\)', '', 'g')
 endfunction
 
+function! ingo#regexp#deconstruct#RemoveMultis( pattern )
+"******************************************************************************
+"* PURPOSE:
+"   Remove multi items (*, \+, etc.) that signify the multiplicity of the
+"   previous atom from a:pattern.
+"* ASSUMPTIONS / PRECONDITIONS:
+"   Does not consider "very magic" (/\v)-style syntax. If you may have this,
+"   convert via ingo#regexp#magic#Normalize() first.
+"* EFFECTS / POSTCONDITIONS:
+"   None.
+"* INPUTS:
+"   a:pattern   regular expression
+"* RETURN VALUES:
+"   Modified a:pattern with multi items removed.
+"******************************************************************************
+    return substitute(a:pattern, '\%(\%(^\|[^\\]\)\%(\\\\\)*\\\)\@<!\%(\*\|\\[+=?]\|\\{-\?\d*,\?\d*}\|\\@\%(>\|=\|!\|<=\|<!\)\)', '', 'g')
+endfunction
+
 let s:specialLookup = {
 \   'e': "\e",
 \   't': "\t",
diff --git a/tests/regexp/deconstruct/t1100-RemoveMultis.vim b/tests/regexp/deconstruct/t1100-RemoveMultis.vim
new file mode 100644
index 0000000..7e9499f
--- /dev/null
+++ b/tests/regexp/deconstruct/t1100-RemoveMultis.vim
@@ -0,0 +1,11 @@
+" Test removing multis.
+
+call vimtest#StartTap()
+call vimtap#Plan(4)
+
+call vimtap#Is(ingo#regexp#deconstruct#RemoveMultis('foobar'), 'foobar', 'no multis')
+call vimtap#Is(ingo#regexp#deconstruct#RemoveMultis('fo\{1,10}bar\? .* l\([aeiou]\)ll\1'), 'fobar . l\([aeiou]\)ll\1', '\? * \{} multis')
+call vimtap#Is(ingo#regexp#deconstruct#RemoveMultis('fo\{-}ba\{-1}r\{-,10} \{2,7}x\\{1,2}'), 'fobar x\\{1,2}', 'various \{} multis')
+call vimtap#Is(ingo#regexp#deconstruct#RemoveMultis('a\@<= foo\(bar\)\@=bar'), 'a foo\(bar\)bar', '\@= multis')
+
+call vimtest#Quit()