grammar.py: Add support for --irrelevant-symbols

Arguments to --irrelevant-symbols are not meant to be represented in the
AST resulting from parsing.

Also, add pad() to misc.py.

Signed-off-by: Jan Lindemann <jan@janware.com>

make/generate-flex-bison.mk

@@ -4,8 +4,9 @@ NAMESPACE_IN_GENERATED ?= $(FB_NAME)
 
 # These types are meant to be cut off the tree and turned into hand coded flex
 # regexes
-#TRIM_SYMBOLS          = blah
-TRIM_SYMBOLS         ?= 
+TRIM_SYMBOLS         ?=
+CUT_SYMBOLS          ?=
+IRRELEVANT_SYMBOLS   ?=
 GENERATE_LOG_LEVEL   ?= notice
 FIX_EXTENSIONS       ?= discard
 CHECK_SYMBOLS        ?= all
@@ -24,6 +25,8 @@ GENERATE              = python ./$(GENERATE_PY) --log-level $(GENERATE_LOG_LEVEL
 				--replace-whitespace \
 				$(OPT_CHECK_SYMBOLS) \
 				--trim-symbols=$(shell echo $(TRIM_SYMBOLS) | sed 's/  */,/g') \
+				--cut-symbols=$(shell echo $(CUT_SYMBOLS) | sed 's/  */,/g') \
+				--irrelevant-symbols=$(shell echo $(IRRELEVANT_SYMBOLS) | sed 's/  */,/g') \
 				--namespace=$(NAMESPACE_IN_GENERATED) \
 				--includes=$(shell echo $(INCLUDED_BY_GENERATED) | sed 's/  */,/g') \
 				$(CREATE_EXTRA_ARGS)