Context

Definition

Source context information used for diagnostics and error reporting.

This module defines the lightweight context type used throughout the fpx preprocessor to associate source-location information with diagnostics, warnings, notes, and error messages.

Every diagnostic emitted by fpx is accompanied by a context object describing where the event occurred. This enables the generation of modern compiler-style messages containing file names, line numbers, source snippets, and caret annotations.

A context captures:

• the original source line,
• the corresponding 1-based line number,
• the path of the source file being processed.

The information stored in a context is consumed primarily by the fpx_logging module to produce precise and user-friendly diagnostics.

For example:

error: undefined macro 'DEBUG'
--> src/main.f90:42
   |
42 | #ifdef DEBUG
   | ^^^^^ not defined

Accurate context information becomes particularly important when processing nested include files, evaluating conditional directives, or reporting errors originating from macro expansions.

Examples

1. Creating a context object:

   type(context) :: ctx
    
   ctx = context( &
   content='real :: x = PI*r**2', &
   line=27, &
   path='src/utils.F90')

2. Using context when reporting diagnostics:

   call printf(render(diagnostic_report( &
   level_error, &
   message='Undefined macro', &
   source=ctx%path), &
   ctx%content, ctx%line))

3. Updating context during include processing:

   included_ctx = context( &
   content=first_line, &
   line=1, &
   path=resolved_include_path)

Data Types
type	context
	Snapshot of a source location within the preprocessing stream. More...