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Pandora-Box

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PostPosted: Mon Oct 03, 2011 10:58 pm
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Thanks Enrico :-)
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Pandora-Box

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PostPosted: Wed Oct 05, 2011 11:13 pm
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Find the crenshaw manual quite intresting but the compiler I got doesnt throw whats the error icon_sad.gif is that because I use free pascal??


Should I start with pascal or ?
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enrico-sorichetti

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PostPosted: Wed Oct 05, 2011 11:21 pm
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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
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Pandora-Box

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PostPosted: Wed Oct 05, 2011 11:49 pm
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I am typing from the scratch using pdf foercasting these syntax will go to my head icon_smile.gif
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enrico-sorichetti

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PostPosted: Wed Oct 05, 2011 11:59 pm
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I just remembered about the wayback machine
and ... tah tah

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

and remember
Code:
http://www.archive.org/web/web.php


great for finding disappeared web pages

and in case You have trubles getting there

here is attached the crenshaw-txt.zip
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Pandora-Box

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PostPosted: Thu Oct 06, 2011 12:20 am
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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 icon_smile.gif
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enrico-sorichetti

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PostPosted: Thu Oct 06, 2011 12:30 am
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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 ...
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Pandora-Box

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PostPosted: Thu Oct 06, 2011 12:36 am
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Can you guide me to some good mauals for BISON or FLEx ?

Never heard of them before icon_sad.gif
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enrico-sorichetti

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PostPosted: Thu Oct 06, 2011 12:57 am
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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
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Pandora-Box

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PostPosted: Thu Oct 06, 2011 1:03 am
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Thanks Enrico:-)
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mtaylor

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PostPosted: Sat Oct 15, 2011 10:52 pm
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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...)
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Pandora-Box

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PostPosted: Sun Nov 06, 2011 9:31 pm
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Thanks Mtaylor icon_smile.gif

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 icon_smile.gif
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prino
Warnings : 1

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PostPosted: Tue Nov 08, 2011 3:47 pm
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enrico-sorichetti wrote:
...
another very interesting article with a completely different approach
is Jack Crenshaw' s Let' s build a compiler, with a PASCAL working sample
it was available until a few months ago at compilers.iecc.com/crenshaw/
but the IECC idiots deleted every trace of it
...

The Wayback Machine is your friend.
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Abid Hasan

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Joined: 25 Mar 2013
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PostPosted: Thu May 22, 2014 11:47 am
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To be honest, I was digging for gold; and guess I ended up with this post. icon_biggrin.gif
Thanks for the info Enrico; thats some good stuff there.
<bookmarked>
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