fortran-shlex

Modern Fortran port of Python's shlex shell-like lexer, now with Windows mslex support.

This package provides two main lexer interfaces:

• shlex: a Unix-style shell lexer, modeled after Python's shlex, and
• mslex: a Windows-style lexer that emulates cmd.exe and CommandLineToArgvW behavior, inspired by the mslex Python module.

🆕 Version 2.0.0 — MSLEX for Windows/DOS-style argument splitting

The new MSLEX API allows parsing and quoting of strings according to Windows command-line conventions, which differ from POSIX shells.

tokens = ms_split(pattern, like_cmd, ucrt, success)

tokens = ms_split(pattern, like_cmd, ucrt, error)

Split a command-line string into arguments using Windows semantics.

Arguments:

• pattern (required): a character(*) input string.
• like_cmd (optional): if .true. (default), emulate both cmd.exe and CommandLineToArgvW.
• ucrt (optional): if .true., parse using UCRT (modern CRT); use msvcrt.dll if .false.. If not provided, both methods are compared and if they differ (ambiguous pattern), an error is raised.
• success (optional): returns .false. if the string is invalid.
• error (optional): alternative error return method, returns a type(shlex_token) containing an error flag and message.

character(len=:), allocatable :: args(:)
logical :: ok

args = ms_split('"my file.txt" -DVALUE=42', like_cmd=.true., success=ok)
if (.not.ok) print *, 'mslex error'

quoted = ms_quote(s, for_cmd)

Quote a string so that it is parsed correctly by Windows command-line interpreters.

• If for_cmd = .true., quotes for cmd.exe, then CommandLineToArgvW.
• If for_cmd = .false., quotes for direct use with CommandLineToArgvW.

print *, ms_quote('my file.txt')                 ! → "my file.txt"
print *, ms_quote('^& dangerous', for_cmd=.true.) ! → "^& dangerous"

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🔧 Install

Just copy and paste shlex_module.f90 into your project. Or, use as a dependency in your Fortran Package Manager project:

[dependencies]
fortran-shlex = { git="https://github.com/perazz/fortran-shlex.git" }

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🐚 POSIX-like Usage (default split / shlex)

tokens = split(string, [success], [error], [join_spaced], [keep_quotes])

Splits a command-like string using Unix shell rules.

character(len=:), allocatable :: tokens(:)
tokens = split('gfortran -I /include "quoted string"')

tokens = shlex(string, [success], [error], [join_spaced], [keep_quotes])

Same as split, but returns an type(shlex_token), allocatable, dimension(:) array.

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📦 Feature Overview

✅ Basic Features

• Handles escaping quotes ("...") and non-escaping quotes ('...')
• Skips newline and carriage return characters
• Returns an array of tokens or structured tokens

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🔧 Version 1.1.0 — join_spaced flag

Use join_spaced=.true. to automatically combine flags and paths like:

tokens = split('gfortran -I /include -L /lib', join_spaced=.true.)
! Result: ["gfortran", "-I/include", "-L/lib"]

Works for any single-letter compiler flags (-I, -L, -D, etc.) where the path does not start with -.

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🔍 Version 1.2.0 — keep_quotes flag

Use keep_quotes=.true. to retain original quoting:

tokens = split('"quoted string" unquoted', keep_quotes=.true.)
! Result: ['"quoted string"', 'unquoted']

Note: if using join_spaced, you must also pass keep_quotes (both arguments required when either is set).

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📜 License

This project is licensed under the MIT License:
See LICENSE-MIT or https://opensource.org/licenses/MIT.

By contributing, you agree that your contributions may be dual licensed under the MIT and Apache-2.0 licenses.

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🔗 See also

• fortran-regex
• Python shlex
• Python mslex
• Golang shlex
• Rust shlex