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From: mertesthomas@gmail.com
Newsgroups: comp.compilers
Subject: Re: Best language for implementing compilers?
Date: Tue, 12 Mar 2019 10:40:02 -0700 (PDT)
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Am Freitag, 8. Februar 2019 16:55:48 UTC+1 schrieb Costello, Roger L.:
> Best language for implementing compilers?

There are language features, which make programming easier.
This is independent of the type of program.

Compilers are big programs. Compilation speed and/or run-time
performance of the generated program can be a goal. But also the
effort (time) to write a compiler must be taken into account.  The
cost to maintain a compiler is also an important factor.  Therefore
the decision for a compiler language is not so easy.

I have written scanners and parsers in C, C++, Java and Seed7.  I have
used C for the scanner and parser of the Seed7 interpreter.  I have
also written scanner, parser and preprocessor for C in Seed7.  The
code generator of the Seed7 compiler is written in Seed7.  My Basic
interpreter, which tokenizes Basic lines, is written is Seed7.

So I have some experience in writing compiler parts in higher (Seed7)
and lower (C) level languages.

Higher level features like memory management help a lot. E.g.: The
Seed7 compiler generates C code. All this C code snippets are held in
strings. The are concatenated and assigned several times, before they
are written out. Doing this in C with manual memory management would
have been a hard task.

So if you want to create a compiler in a reasonable time I suggest you
prefer a higher level language.

If compilation speed is the criteria number one you will probably need
to use C (to squeze every cycle out of the machine). This is what I
did, when implementing the front end of the Seed7 interpreter.

I designed some language features of Seed7, to support scanning and
parsing. E.g.: Every file in Seed7 has a bufferChar. A bufferChar is
just a single character attached to the file.  If you use LL(1)
parsing for tokens you read a character and assign it to the
bufferChar. Then, depending on the bufferChar, you decide what to do
next. If the bufferChar is a digit you will read a number. If the
bufferChar is a letter you will read an identifier. Etc. Examples of
such scanner functions can be found in the library scanfile.s7i.

Regards,
Thomas Mertes

--
Seed7 Homepage:  http://seed7.sourceforge.net
Seed7 - The extensible programming language: User defined statements
and operators, abstract data types, templates without special
syntax, OO with interfaces and multiple dispatch, statically typed,
interpreted or compiled, portable, runs under linux/unix/windows.