I'd like Walter to reply to this. In his article here
http://www.drdobbs.com/architecture-and-design/so-you-want-to-write-your-own-language/240165488
Walter says
Somewhat more controversial, I wouldn't bother wasting time
with lexer or parser generators and other so-called "compiler
compilers." They're a waste of time. Writing a lexer and parser
is a tiny percentage of the job of writing a compiler. Using a
generator will take up about as much time as writing one by
hand, and it will marry you to the generator (which matters
when porting the compiler to a new platform). And generators
also have the unfortunate reputation of emitting lousy error
messages.
I have no idea how to write one. First off when I originally
tried before using anything I wrote nonsense code. Second is I
couldn't tell if I had a conflict (either shift reduce or reduce
reduce) or if I wrote it wrong/badly. Third is I'm not sure how a
tiny one should look like and my language is fairly large. I
already understand flex and bison. I'm planning to rewrite from
scratch so I could attempt doing so on my own but I don't know
how to deal with the above.
I just looked at parse.c and I had no idea there is a precedence
table. Why is there one rather than it being embedded like a
switch statement which tries to handle all the higher precedence
operations calling a function running the next set of precedence?
I guess that does sound like a loop/table but I imagined it in
switch statements.
Using bison I can write complex statements which are easy for me
to grok and change. I wouldn't know how to change complex
statements if I hand wrote the parser. I don't know all the
places something like that would affect. Taking the syntax below
I'm not sure how to fork a state and discard the invalid one.
foo[5] = var2
foo[5] foo = var2
Here when I see foo[5] I'm either accessing an array (first
statement) or declaring variables as an array of 5 elements
(second statement). Just like `Foo&foo` could be a reference or
could be an AND statement. Foo is definitely processed on its
own, I don't know how to process it as both (a fork) and continue
on the parser to find a valid path.
My bison file has >2000 states. I'm not sure how much work it may
mean if I handwrote my parser.
