build_cannonical

#!/bin/ash
alias_file="$(realpath ~/cat_test_alias.in)"
ALIAS_FNS="$(awk -v  ALIASFILE="$alias_file" '
function add_get_canonical_hdr(){
  print "function get_canonical_name(s){                  "
  print "  if (s in CANONICAL_ARY){                       "
  print "   return CANONICAL_ARY[s]                       "
  print "  } else {                                       "
  print "    switch(s){                                   "
}
function add_get_canonical_footer(){
  print "  }                                              "
  print "  return s                                       "
  print "}                                                "
}
function add_canonical_case(s,name){

  #TODO: Do this untill there is no astrixs left to replace.
  s=gensub(/^(.*[^.*])(\*)(.*)$/,"\\1.*\\3","G",s) # replace "*" with ".* "
  s=gensub(/^(.*[^\\+])(\+)(.*)$/,"\\1\\\\+\\3","G",s) # replace "+" with "\+"
  print "      case /" s "/:                              "
  print "        return \"" name "\"                          "
}
function write_CANONICAL_ARY_init_hdr(){
  print "init_CANONICAL_ARY(){                            "
}
function write__init_CANONICAL_ARY(){
  print "init_CANONICAL_ARY(){                            "
  for (p in CANONICAL_ARY){
    print "  CANONICAL_ARY[\"" p "\"]=\"" CANONICAL_ARY[p] "\""
  }
  print "}"
}


#This writes the start of the function get_canonical_name()
#this function will return a single name for all equivalent alias values.
BEGIN { FS = ","; add_get_canonical_hdr()}

#If wild cards are used in an alias get_canonical_name() uses regX case statments to do the match.
#Otherwise get_cannonical_name() looks up the value in an associative array (AKA dictonary or hashmap)
{
  canonical_NAME=$1
  sub(/\*/,"",canonical_NAME) #This isn'"'"'t necissary but makes the key slightly nicer looking
  for(i=NF;i>=1;i--){
    if(index($i,"*")>0){
      add_canonical_case($i,canonical_NAME) #alias has a wild card so wirite case statement to match alias
    }
    else{
      CANONICAL_ARY[$i]=canonical_NAME #alias has no wild card so add to lookup array)
    }
  }
}
END {add_get_canonical_footer()
     write__init_CANONICAL_ARY()
    } ' "$alias_file")"

echo "$ALIAS_FNS"