18 Jun
2026
18 Jun
'26
7:19 p.m.
On Thu, 2026-06-18 at 14:30 -0400, Paul Koning via cctalk wrote:
The NAG Fortran compiler generates C. It does a reasonable job of
telling gdb where things are. At least I've successfully used gdb with
it. The generated code is pretty good, although not as good as a native
compiler such as ifx, because there are things that Fortran "knows"
about your code that it simply cannot explain in C. nagfor is the
pinnacle of outstanding compile time and run time diagnostics. But it
was written by, and is entirely maintained by, one guy: Malcolm Cohen.
For a time he had a colleague who developed and maintained the runtime
library. Of course, all the math stuff comes from the NAG library. He
has mentioned writing a native code generator instead of C, but he's
not done it yet. And by using C he provides the compiler for Linux,
Windoze, and MacOS. He frequently laments C compilers' imaginative
interpretations of the C standard, especially what gcc believes "ISO
standard C" actually means. He's also the project editor for the
Fortran standard. I wish I had had his energy when I was his age, let
alone at my age now.
As for translating from one language to another,
that was pretty
much
standard practice for a long time. GNAT Ada produced C. P2C
converted
Pascal to C. F2C the same for Fortran. Early precursors of GNU
COBOL
did the same. Assembler knowledge is not necessarily needed to
write
a compiler if you have another language to function as the
intermediate
stage of the compiler.
True, but that approach has significant drawbacks and from where I
sit it appears more like a technique that was used for a while as a
shortcut to implementing a language. All the examples you gave are
now obsolete, at least in the GCC system, replaced by full front ends
that tie into the code generation machinery. A reason why this
matters is debug info; having C debug info for your Fortran program,
let alone COBOL or Pascal, is painful. Another reason is semantic
mismatches. C doesn't like nested function definitions (though GCC
sort of allows them as an extension) while other languages (Algol for
sure, and Pascal also I think) consider them perfectly good things to
do.