[completion] A harness to test _init_completion from bash-completion.

This is the API that completion plugins use.  It fills in 4 or 5
variables, and then the plugins set COMPREPLY.

_init_completion has a nasty shell implementation, which we can replace
in OSH with simple Python code.

gold/init_completion.sh

@@ -0,0 +1,61 @@
+#!/bin/bash
+#
+# Test our _init_completion builtin against the bash_completion implementaiton.
+#
+# Usage:
+#   ./init_completion.sh <function name>
+
+tab-complete() {
+  local code=$1
+  local sh=bash
+  #local sh=bin/osh
+
+  local pat='^FLAGS|^COMP_WORDS|^WORDS|^VAR'
+  { cat gold/init_completion_lib.sh; echo "$code"; } |
+    $sh --rcfile /dev/null -i 2>&1 |
+    egrep "$pat" || echo "ERROR: output didn't match $pat"
+}
+
+# _init_completion flags used:
+# -s
+# -n :
+#
+# Do NOT need to implement:
+#
+# -o '@(diff|patch)' is used once.  But it's for redirect args, which we parse
+# in OSH itself.
+#
+# NOTE: I see _init_completion -s -n : , but I believe that's identical to
+# _init_completion -s.
+# Also I see '-n =+!' once, but that may be a mistake.  The most common cases
+# are : and =.
+
+test-init() {
+  tab-complete $'echo foo:bar --color=auto\t'
+
+  # readline includes quotes, and _init_completion doesn't do anything about this.
+  # I think that is a mistake and I will get rid of it?
+  #
+  # ls "--ver<TAB> or '--ver<TAB>' does NOT complete.
+  # But echo 'fro<TAB> DOES!  So that is a mistake.
+
+  tab-complete $'echo "foo:bar|" --color=auto\t'
+
+  # scrape tab completion
+  echo
+  tab-complete $'noflags foo:bar --color=auto\t'
+  tab-complete $'noflags "foo:bar|" --color=auto\t'
+  tab-complete $'noflags "foo:bar|\t'
+
+  echo
+  tab-complete $'s foo:bar --color=auto\t'
+  tab-complete $'s foo:bar --color auto\t'
+
+  echo
+  tab-complete $'n foo:bar --color=auto\t'
+
+  echo
+  tab-complete $'n2 foo:bar --color=auto\t'
+}
+
+"$@"

gold/init_completion_lib.sh

@@ -0,0 +1,50 @@
+# Common functions fed to 'sh -i' by init_completion.sh.
+
+# OSH should have this built in
+if ! type -t _init_completion; then
+  source testdata/completion/bash_completion
+fi
+
+argv() {
+  python -c 'import sys; print(sys.argv[1:])' "$@"
+}
+comp_echo() {
+  echo
+  echo -n 'COMP_WORDS '; argv "${COMP_WORDS[@]}"
+}
+complete -F comp_echo echo
+
+showvars() {
+  echo -n 'WORDS '; argv "${words[@]}"
+  echo -n 'VAR '; argv cur "$cur"
+  echo -n 'VAR '; argv prev "$prev"
+  echo -n 'VAR '; argv cword "$cword"
+  echo -n 'VAR '; argv split "$split"
+}
+
+_comp_init_completion() {
+  local cur prev words cword split
+
+  echo
+  echo FLAGS "$@"
+  _init_completion "$@"
+
+  echo
+  showvars
+}
+
+noflags() { echo; }
+comp_noflags() { _comp_init_completion; }
+complete -F comp_noflags noflags
+
+s() { echo; }
+comp_s() { _comp_init_completion -s ; }
+complete -F comp_s s
+
+n() { echo; }
+comp_n() { _comp_init_completion -n = ; }
+complete -F comp_n n
+
+n2() { echo; }
+comp_n2() { _comp_init_completion -n := ; }
+complete -F comp_n2 n2

misc/complete.sh

@@ -58,7 +58,7 @@ audit-git() {
 
 # EVERY plugin seems ot use the _init_completion function.  We can do this
 # ourselves!
-audit-plugins() {
+audit-plugin-init() {
   ls ../bash-completion/completions/* | wc -l
   #grep -c _init_completion ../bash-completion/completions/* 
 
@@ -75,7 +75,9 @@ audit-plugins() {
   grep --no-filename _init_completion \
     $BASH_COMP ../bash-completion/completions/* |
     sort | uniq -c | sort -n
+}  
 
+audit-plugin-x() {
   echo
   echo '-X usage'
   echo