Merge pull request #558 from nwinkler/alias-completion

Added alias-completion plugin

plugins/available/alias-completion.bash

@@ -0,0 +1,82 @@
+cite about-plugin
+about-plugin 'Automatic completion of aliases'
+
+# References:
+# http://superuser.com/questions/436314/how-can-i-get-bash-to-perform-tab-completion-for-my-aliases
+# http://stackoverflow.com/a/1793178/1228454
+
+# This needs to be a plugin so it gets executed after the completions and the aliases have been defined.
+# Bash-it loads its components in the order
+# 1) Aliases
+# 2) Completions
+# 3) Plugins
+# 4) Custom scripts
+
+# Automatically add completion for all aliases to commands having completion functions
+function alias_completion {
+    local namespace="alias_completion"
+
+    # parse function based completion definitions, where capture group 2 => function and 3 => trigger
+    local compl_regex='complete( +[^ ]+)* -F ([^ ]+) ("[^"]+"|[^ ]+)'
+    # parse alias definitions, where capture group 1 => trigger, 2 => command, 3 => command arguments
+    local alias_regex="alias ([^=]+)='(\"[^\"]+\"|[^ ]+)(( +[^ ]+)*)'"
+
+    # create array of function completion triggers, keeping multi-word triggers together
+    eval "local completions=($(complete -p | sed -Ene "/$compl_regex/s//'\3'/p"))"
+    (( ${#completions[@]} == 0 )) && return 0
+
+    # create temporary file for wrapper functions and completions
+    rm -f "/tmp/${namespace}-*.tmp" # preliminary cleanup
+    local tmp_file; tmp_file="$(mktemp "/tmp/${namespace}-${RANDOM}XXX.tmp")" || return 1
+
+    local completion_loader; completion_loader="$(complete -p -D 2>/dev/null | sed -Ene 's/.* -F ([^ ]*).*/\1/p')"
+
+    # read in "<alias> '<aliased command>' '<command args>'" lines from defined aliases
+    local line; while read line; do
+        eval "local alias_tokens; alias_tokens=($line)" 2>/dev/null || continue # some alias arg patterns cause an eval parse error
+        local alias_name="${alias_tokens[0]}" alias_cmd="${alias_tokens[1]}" alias_args="${alias_tokens[2]# }"
+
+        # skip aliases to pipes, boolan control structures and other command lists
+        # (leveraging that eval errs out if $alias_args contains unquoted shell metacharacters)
+        eval "local alias_arg_words; alias_arg_words=($alias_args)" 2>/dev/null || continue
+        # avoid expanding wildcards
+        read -a alias_arg_words <<< "$alias_args"
+
+        # skip alias if there is no completion function triggered by the aliased command
+        if [[ ! " ${completions[*]} " =~ " $alias_cmd " ]]; then
+            if [[ -n "$completion_loader" ]]; then
+                # force loading of completions for the aliased command
+                eval "$completion_loader $alias_cmd"
+                # 124 means completion loader was successful
+                [[ $? -eq 124 ]] || continue
+                completions+=($alias_cmd)
+            else
+                continue
+            fi
+        fi
+        local new_completion="$(complete -p "$alias_cmd")"
+
+        # create a wrapper inserting the alias arguments if any
+        if [[ -n $alias_args ]]; then
+            local compl_func="${new_completion/#* -F /}"; compl_func="${compl_func%% *}"
+            # avoid recursive call loops by ignoring our own functions
+            if [[ "${compl_func#_$namespace::}" == $compl_func ]]; then
+                local compl_wrapper="_${namespace}::${alias_name}"
+                    echo "function $compl_wrapper {
+                        (( COMP_CWORD += ${#alias_arg_words[@]} ))
+                        COMP_WORDS=($alias_cmd $alias_args \${COMP_WORDS[@]:1})
+                        (( COMP_POINT -= \${#COMP_LINE} ))
+                        COMP_LINE=\${COMP_LINE/$alias_name/$alias_cmd $alias_args}
+                        (( COMP_POINT += \${#COMP_LINE} ))
+                        $compl_func
+                    }" >> "$tmp_file"
+                    new_completion="${new_completion/ -F $compl_func / -F $compl_wrapper }"
+            fi
+        fi
+
+        # replace completion trigger by alias
+        new_completion="${new_completion% *} $alias_name"
+        echo "$new_completion" >> "$tmp_file"
+    done < <(alias -p | sed -Ene "s/$alias_regex/\1 '\2' '\3'/p")
+    source "$tmp_file" && rm -f "$tmp_file"
+}; alias_completion