Path: utzoo!utgpu!attcan!uunet!mcvax!unido!ecrcvax!micha
From: micha@ecrcvax.UUCP (Micha Meier)
Newsgroups: comp.lang.prolog
Subject: Re: Pascal/C -vs- Prolog
Message-ID: <607@ecrcvax.UUCP>
Date: 3 Aug 88 11:06:20 GMT
References: <184@quintus.UUCP>
Reply-To: micha@ecrcvax.UUCP (Micha Meier)
Organization: ECRC, Munich 81, West Germany
Lines: 30

In article <184@quintus.UUCP> ok@quintus () writes:
>A fast compiler is well worth having, but I think it is better for Prolog
>users in the long run if vendors try to make faster compilers *in Prolog*.

	I absolutely agree, but the question I am raising is
	"is that possible?" and "how can it be done?".
	I definitely don't have a 20 years'
	experience with programming in C (I knew Prolog before C),
	and I haven't tried to write the compiler in Prolog; however,
	I've seen quite a few Prolog compilers in Prolog, and all of them
	are really *slow* compared to the C version. I suggest that
	people analyze their Prolog compilers and share the experiences,
	because as long as the compilers in Prolog cannot compete the
	ones in C, Prolog cannot be claimed to be 'the compiler
	implementation language'. I know that lot of people will say
	that a compiler in Prolog is more readable, better maintainable
	etc., but so is my Sepia compiler in C. Bruno has already noted
	that his compiler spends the majority of time in managing the
	database (record*), and of course in C is this much easier.

	My compilers spends 56 units in the lexical analysis, 90 units
	in parsing, 47 units in the second pass and 25 units in the
	code generation (and other units elsewhere). This looks like
	the first pass is the most expensive one (I'm not a compiler
	expert :-)). How is it in a compiler written in Prolog?
	Are other compilers in C similar?
	(units measured compiling CHAT-80).


--Micha