CPSC 411			ASSIGNMENT # 1
Winter 2001
Lec ??
Lab 02

Student: Chad C. D. Clark	< clarkch @ cpsc . ucalgary . ca >
Date: Jan 28, 2002


Synopsis: A minusculus compiler written in pure C that generates stack
	machine code as defined in file AS1.SPECS.

NOTE: I did use the _OLD_ grammar.  Though the rules do get manipulated a
	bit.  Refer to source code comments for term, expr and, stmtlist.

Input: Reads minusculus source code from STDIN.
Output: Writes stack machine target code to STDOUT.
	Errors (including warnings) are reported to STDERR.

Files:
	README - contains info about this project and tarball.
	AS1.SPECS - copy of the assignment in text format.
	AS1.GRAMMAR - new grammar (non left-recursive).
	as1lex.l - the lexer and main() routine.
	as1parse.c - performs the parsing and syntax tree construction.
	as1tree.c - function that deal with building the tree and traversing.
	as1globals.h - info used by more than one file.
	as1tokens.h - defines the token types used by the lexer and parser.
	as1tree.h - defines node types and tree functions.
	makefile - pretty standard makefile.
	tests/ - directory with many test files.
	tests/do-tests - script to run the tests found in tests directory.

Compiling:
	Just use the command "make".
	"make clean" deletes lex.yy.c, *.o and a.out
	"make stats" counts source file lines.

	Requires flex and gcc
	- Developed with:
	  - flex 2.5.4
	  - egcs 2.91.66
	  - gdb 4.18

Postmortum: (Mostly for my benifit but I wanted to keep this next to the code.)

	Things that went well:
	- Writing the tree pointer code.  Only one null pointer error!
	  It was due to not checking for NULL and not having an END_NODE.
	- Writing the lexer.  LEX rocks!

	Things that went not so well:
	- Getting the shape of the tree stucture down in my mind.  I was
	  starting to get two disjoint models (parse code and node building
	  code) then I sat down, drew pictures and, traced out tree traversals
	  untill I had a model.  Then writing down a record of the model for
	  reference.
	- Realizing C unlike C++ requires 'struct' before every declaration.

	Things that were usefull:
	- Drawing pictures (trees in particular).
	- Writing down plans, decisions and models for reference in other 
	  parts of the program.
	- Writing code on paper before typing it up.
	- GDB and the GDB book by Stallman and Pesch.
	- syntax highlighting & 60 row console mode

	Things I would like to do differently on future projects:
	- Sit down and plan out the structure of the program before writing
	  code.
	- Document my data structures before using them.  It's easier than
	  searching with grep and opening up an editor.

	Things I learned:
	- A nice (ie non left recursive grammar) is very usefull.
	- Follow sets can make parsing much easier.

	Things I want to learn:
	- How to let flex let me define main() outside of the .l file.