fgof-lineedit

Fortran-native line editing helpers for interactive CLI tools.

fgof-lineedit is intended to be a small, standalone library that gives Fortran shells, REPLs, and interactive CLIs a friendlier editing surface than raw terminal reads.

It is part of the FortranGoingOnForty lib-modules catalog, but it is intended to stand on its own as a normal fpm package.

Current v1 target:

• editable line buffer and cursor model
• prompt handling and rendered line state
• history navigation and history storage hooks
• completion and key-handling integration points
• clean boundaries with future fgof-termios and fgof-keys

Future scope:

• richer readline-style editing commands
• completion engines and menu UIs
• prompt widgets and multi-line editing

Status

Initial scaffold is in place.

Implemented today:

• public fgof_lineedit and fgof_lineedit_types modules
• line editor, action, completion, history, prompt, and render-state types
• prompt constructor, editable buffer core, cursor movement and deletion helpers, word-wise navigation, history navigation, action dispatch, completion helpers, completion-menu state, accept helpers, and render snapshots
• smoke-test coverage and CI wiring

Still to implement:

• terminal integration and redraw policy
• richer completion menus and callback policies

Why Use It

• line editing is repeatedly hand-built in shells, REPLs, and text tools
• the Fortran ecosystem still lacks an obvious small default package here
• it is meant to compose cleanly with fgof-pty, future fgof-termios, and future fgof-keys

Public API Shape

Primary modules:

• fgof_lineedit
• fgof_lineedit_types

Public types:

• completion_item
• completion_span
• lineedit_action
• lineedit_render_completion
• lineedit_render_state
• lineedit_state
• prompt_spec
• history_entry

Action constants:

• FGOF_LINEEDIT_ACT_NONE
• FGOF_LINEEDIT_ACT_INSERT
• FGOF_LINEEDIT_ACT_DELETE_LEFT
• FGOF_LINEEDIT_ACT_DELETE_RIGHT
• FGOF_LINEEDIT_ACT_DELETE_WORD_LEFT
• FGOF_LINEEDIT_ACT_DELETE_WORD_RIGHT
• FGOF_LINEEDIT_ACT_MOVE_LEFT
• FGOF_LINEEDIT_ACT_MOVE_RIGHT
• FGOF_LINEEDIT_ACT_MOVE_WORD_LEFT
• FGOF_LINEEDIT_ACT_MOVE_WORD_RIGHT
• FGOF_LINEEDIT_ACT_MOVE_HOME
• FGOF_LINEEDIT_ACT_MOVE_END
• FGOF_LINEEDIT_ACT_HISTORY_PREVIOUS
• FGOF_LINEEDIT_ACT_HISTORY_NEXT

Current public procedures:

• accept_line
• add_history_entry
• apply_completion
• apply_selected_completion
• apply_action
• buffer_length
• clear_completion_menu
• completion_count
• completion_span_at_cursor
• delete_word_left
• delete_word_right
• set_buffer
• set_completion_items
• insert_text
• insert_action
• delete_left
• delete_right
• default_prompt
• history_count
• history_previous
• history_next
• init_lineedit
• move_cursor_left
• move_cursor_right
• move_cursor_word_left
• move_cursor_word_right
• move_cursor_home
• move_cursor_end
• lineedit_completion_provider
• render_lineedit
• refresh_completion_menu
• reset_lineedit
• select_next_completion
• select_previous_completion
• simple_action

Quick Start

program demo_lineedit
  use fgof_lineedit, only : &
    default_prompt, &
    init_lineedit, &
    lineedit_render_state, &
    lineedit_state, &
    render_lineedit, &
    set_buffer
  implicit none

  type(lineedit_state) :: editor
  type(lineedit_render_state) :: view

  call init_lineedit(editor, default_prompt("> "))
  call set_buffer(editor, "build", 3)
  view = render_lineedit(editor)
  print "(A)", view%line
  print "(I0)", view%cursor_column
end program demo_lineedit

Build And Test

fpm test

That is the baseline verification command locally and in CI.

Supported Platforms

• macOS
• Linux

Boundaries

• intended to stay independently versioned and releasable
• focused on editing state and library ergonomics, not full shell implementation
• terminal-mode control should stay in a future companion package

Notes

• lineedit_state is a public Fortran type, so callers can mutate fields directly. The helper procedures are the safer path when you want cursor, history, completion, and render-state invariants to stay aligned.

License

MIT