Read and Configure the Status Bar

This chapter reads buffer safety, position, Project, Workspace, and language context from the active pane, invokes admitted segment actions, changes the factory layout, and verifies deterministic behavior in narrow geometry.

Before You Begin

If you enter this chapter directly, first complete Prepare the User Guide Exercises.

Complete Select and Read a Theme. Open the maintained User Guide Workspace, select Forecast Engine/main.odin, and keep Darek visible beside the source pane.

The exercise kit supplies this Workspace and Project file. The configuration source introduced later is pasted by the reader from its complete block.

The Status Bar belongs to one pane. It observes current state from the buffer, view, Project, Workspace, and language owners without owning or mutating any of them.

Read the Active Pane

At ordinary width, read the Status Bar from left to right:

704 src/ main.odin 18:7 22%       W:User Guide P:Forecast Engine UTF-8 LF Odin LS

The exact values depend on the active document. The left group presents buffer size, Project-relative directory, filename, one-based line and display column, and viewport position. The right group presents only available Workspace, Project, encoding, language, service, and diagnostic context.

Move point and scroll. Position and Top, Bot, or percentage update from the active view. Press M-t to focus Darek, then return to the source pane. Each pane presents its own buffer and view context; the selected theme distinguishes the active row from inactive rows.

Unavailable context is absent. A document outside the active Project does not acquire invented Project or Workspace labels.

Read Safety and Language State

Insert one character. ** appears before the filename while the document differs from its saved base. Press C-/ to restore the clean revision and observe the marker disappear.

In a read-only or modified read-only context, %% or %* distinguishes write policy from modification state. These markers report state; they are not text and cannot change the buffer when selected or copied.

For a supported source document, the editing-context segment begins with the language. An active language service adds LS; current error and warning totals appear as E and W. Initializing, failed, and stopped service states are explicit when current observations provide them.

Inspect Visible Segments

Run M-x status-bar-inspect. The shared candidate surface lists the exact segments composed for the active pane generation. Type part of a label or inspection value to filter, move with C-n, C-p, Down, or Up, and press RET.

Odra returns to the editor and places the selected bounded inspection value in the shared feedback region. Press C-g instead to cancel without changing the editing context.

Invoke an Admitted Action

Run M-x status-bar-actions. Only visible segments whose owning subsystem has an admitted primary command appear. The buffer identity opens buffer navigation; Project and language context delegate to their ordinary command surfaces.

Select one action with RET, then return to the document. The candidate captures the exact Status Bar and command-registry generations. If either changes before acceptance, Odra rejects the stale row instead of invoking a different action.

Observe Narrow-Pane Policy

Reduce the terminal width or split the source again. The Status Bar applies one deterministic sequence:

• use admitted compact forms;
• omit optional low-priority context;
• truncate the buffer label at a complete grapheme and append …; and
• retain alerts, buffer safety, identity, and compact position.

Restore the width. Full forms return from current observations. Narrow presentation never changes the underlying buffer, Project, Workspace, or language state.

Configure the Factory Layout

Open ~/odra-guide/config/odra/init.rkt. Preserve existing exports and add this complete Status Bar policy:

(provide odra-status-bar-configuration)

(define odra-status-bar-configuration
  '#hash((position . line-column)
          (visible . (project editing-context))
          (compact . prefer-compact)))

Save the file, restart Odra, and reopen the tutorial Workspace. Position now uses line:column without a percentage, only Project and editing context are eligible among optional segments, and their compact forms are preferred.

The admitted position policies are line-column-percentage, line-column, and byte-offset. Visibility may include encoding, pane-state, workspace, project, and editing-context. Compact policy may be automatic, prefer-compact, or essential-only.

Introduce an invalid value, restart, and observe the bounded configuration diagnostic. The complete candidate is rejected and the factory presentation remains active. Restore the valid policy before continuing.

Recover from Status Bar Problems

• If expected context is absent, verify the active pane, buffer association, Project or Workspace membership, and current language publication.
• If an action list is empty, inspect segments first; informational segments need not expose an action.
• If an accepted candidate is stale, reopen the command to capture current segment and command generations.
• If a label disappears in narrow geometry, restore width before treating the omitted optional segment as unavailable state.
• If personal configuration is rejected, correct the complete exported value and restart; partial policy is never applied.

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