Line

Definition

Standard #line directive support for the fpx Fortran preprocessor.

This module implements full support for the ISO C99/C11 #line directive, which is also widely used in Fortran preprocessors.

The #line directive allows changing the logical line number and/or source filename reported by the preprocessor. It is particularly useful for:

• Code generators
• Literate programming tools
• Macro-heavy generated code
• Accurate __LINE__ and __FILE__ expansion in included/generated files

Supported forms (standard compliant):

• #line <number>
• #line <number> "<filename>"

When a #line directive is encountered, the current context (line number and filename) is updated immediately. This affects all subsequent diagnostics, __LINE__, __FILE__, and __FILENAME__ macros.

Examples

1. Basic line number reset:

   #line 100
   print *, 

2. Changing both line number and filename (common in generated code):

   #line 42 
   integer :: x = 1   ! this will appear as line 42 in generated_code.f90

Remarks

• The line number in #line N refers to the next line after the directive.
• Filename must be quoted if provided.
• Invalid line numbers or malformed directives emit a warning but are ignored.
• Updates the shared context object used by the logging and macro systems.

Methods

handle_line()

subroutine handle_line ( type(context), intent(inout) ctx, character(*), intent(in) token )

private

Handle the standard line directive Supports two standard forms: line <number> line <number> "<filename>".

This updates the current line number (ctxline) and optionally the current filename (ctxpath) for subsequent diagnostics, __LINE__, and __FILE__ expansions.

Fully compliant with ISO C99 / C11 �6.10.4 and common Fortran preprocessor behavior.

Parameters

[in,out]	ctx	Context source line containing the line directive
[in]	token	Usually 'DEFINE' � keyword matched in lowercase

Remarks

Definition at line 67 of file line.f90.