compiler construction chat

Pandora-Box · Posted: Mon Oct 03, 2011 10:58 pm

Thanks Enrico :-)

Pandora-Box · Posted: Wed Oct 05, 2011 11:13 pm

Find the crenshaw manual quite intresting but the compiler I got doesnt throw whats the error

is that because I use free pascal??

Should I start with pascal or ?

enrico-sorichetti · Posted: Wed Oct 05, 2011 11:21 pm

some time ago I played with it using free pascal and I do not remember having any trouble

what version of the crenshaw stuff did You find the zipped one in text format ?
or You are typing from scratch using the PDF one

Pandora-Box · Posted: Wed Oct 05, 2011 11:49 pm

I am typing from the scratch using pdf foercasting these syntax will go to my head

enrico-sorichetti · Posted: Wed Oct 05, 2011 11:59 pm

I just remembered about the wayback machine
and ... tah tah

web.archive.org/web/20110725224253/http://compilers.iecc.com/crenshaw/

and remember

Pandora-Box · Posted: Thu Oct 06, 2011 12:20 am

Thanks Enrico :-) and to be frank with you Crenshaw's language is a bit high as for me to comprehend anyway am googling to get more info

enrico-sorichetti · Posted: Thu Oct 06, 2011 12:30 am

well it' s some kind of religion war
top down parsing
and LALR parsing - flex bison semi BNF

You might ry a different path as ..
start exercising with flex a bit of patten matching
after that continue with bison ( the simple calculator )

what You get by building the simple calculator is an interpreter ,
after that expanf the calculator with simple if logic
and ...
and ...

Pandora-Box · Posted: Thu Oct 06, 2011 12:36 am

Can you guide me to some good mauals for BISON or FLEx ?

Never heard of them before

enrico-sorichetti · Posted: Thu Oct 06, 2011 12:57 am

for bison the official GNU manual here
www.gnu.org/software/bison/manual/
and here the same for flex
flex.sourceforge.net/manual/

anyway I got curious, reinstalled everything from scratch
and everything worked up to tutor5

to save some typing

I would start with the old lex and yacc downloading the sources of the examples from the o' reilly site here
shop.oreilly.com/product/9781565920002.do
and click on the Download Example Code
it will keep You busy for a while
after You have mastered the examples You will be ready for the next step

Pandora-Box · Posted: Thu Oct 06, 2011 1:03 am

Thanks Enrico:-)

mtaylor · Posted: Sat Oct 15, 2011 10:52 pm

I've spent a lot of time with the parsing bit of compiler impl. Here's my take on the resources mentioned so far:

Dragon Book: all theory, I didn't find it very useful. Yeah it's good to know, but if you aren't implementing lexers and LALR parser generators it's a bit much. The lex/yacc tutorial linked above is a good intro, but to use the tools you'll be coding in C. The dual stack nature of table driven yacc parser can be hard to grasp at first

Crenshaw: goes thru building recursive descent parsers. It's a bit long winded because he goes thru and rewrites the same parser several times, but it's a good intro to dop down parsing. ANTLR is the current popular recursive descent parser generator, Javacc and Coco/R also good alternatives.

FWIW, recursive descent is used a lot because it provides a lot more flexibility in parsing languages like C++ which is very difficult (many ph.d thesis have been written about parsing c++). For example, llvm c/c++ frontend (clang) is a hand coded recursive descent parser.

Here's an exmple of a recursive descent parser in Python, includes an interpreter that walks the AST:

www.jroller.com/languages/entry/python_writing_a_compiler_and

But, parsing is only about 1/3 of a compiler, the other 2/3's are also very challenging (register allocation, code optimization, etc...)

Pandora-Box · Posted: Sun Nov 06, 2011 9:31 pm

Thanks Mtaylor

I have started with something which I have some idea on that is "C" If you experts can guide on path of that will be helpful

prino · Posted: Tue Nov 08, 2011 3:47 pm

Abid Hasan · New User Joined: 25 Mar 2013 Posts: 88 Location: India

To be honest, I was digging for gold; and guess I ended up with this post.

Thanks for the info Enrico; thats some good stuff there.
<bookmarked>