Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.compilers > #2327
| From | steve kargl <sgk@troutmask.apl.washington.edu> |
|---|---|
| Newsgroups | comp.compilers |
| Subject | Re: Regular expressions in lexing and parsing Fortran |
| Date | 2019-05-22 04:12 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <19-05-096@comp.compilers> (permalink) |
| References | <19-05-092@comp.compilers> <19-05-095@comp.compilers> |
Hans-Peter Diettrich wrote: > OTOH I wonder how a formal (regex?) FORTRAN lexer grammar could look like? > > [I've written Fortran 77 parsers. It was quite context sensitive, particularly > deciding whether a statement was an assignment or something else. e.g. > > FORMAT(I4) = 42 > DO 10 I = 1.23 (oops) > > Modern Fortran no longer ignores spaces which makes lexing a lot easier. -John] Fortran supports two forms. Fixed source form is what might be called the legacy form, where spaces are ignored. Spaces are significant for free source form. See Section 6.3 of the Fortran 2018 standard (ie, N2146.pdf). So, yes, a Fortran compiler has two lexer/parsers. -- steve
Back to comp.compilers | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Regular expressions in lexing and parsing Ed Davis <ed_davis2@yahoo.com.dmarc.email> - 2019-05-17 13:18 +0000
Regular expressions in lexing and parsing Ben Hanson <jamin.hanson@googlemail.com> - 2019-05-18 13:24 +0100
Re: Regular expressions in lexing and parsing Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2019-05-21 07:14 +0200
Re: Regular expressions in lexing and parsing Fortran steve kargl <sgk@troutmask.apl.washington.edu> - 2019-05-22 04:12 +0000
Re: Regular expressions in lexing and parsing "Ev. Drikos" <drikosev@gmail.com> - 2019-05-23 18:42 +0300
csiph-web