DSPF-edit

DSPF-edit brings a live schema view, a drag-and-drop screen preview, and deep DDS keyword coverage to editing IBM i display files — right inside VS Code. No more counting columns in SEU, no more round-trips through STRSDA on a 5250 session, no more guessing how a WINDOW, an indicator condition, or a CHOICE() field will actually render until you compile.

Why DSPF-edit?

DSPF-edit doesn't replace your compiler — it closes the gap between writing DDS and seeing the screen it produces, matching real STRSDA behavior field by field, so what you preview is what you get.

✨ Features

🖥️ Screen Preview — see it before you compile

• Visual, green-screen-style preview of a record's fields and constants (colors, DSPATR attributes, and placeholders for output/input/both fields).
• A field coded with CNTFLD(n) wraps across multiple lines in the preview, n characters each, all starting at its original column — matching how RDi previews it.
• A single, compact toolbar (size, display format, overlay, indicators, add buttons) sits above the preview.
• Drag fields/constants to reposition them directly on the preview.
• "+ Field" / "+ Constant" buttons: click, then click a point on the screen to place a new field/constant there, using the same prompts as the tree's "Add field"/"Add constant" commands.
• WINDOW records are drawn at their real screen position and can be resized/moved with the mouse; shows WDWTITLE if present. Supports windows shared via WINDOW(record-name).
• Click a window's title to edit it, or use its "⋮" actions menu / one-click "center horizontally" icon — all shown only while hovering over the window.
• Subfile (SFL/SFLCTL) records show all SFLPAG rows, and automatically preview their paired header/detail record; detail rows can't be dragged up over the header's own content.
• Overlay any other record (dimmed) behind the one being previewed, to see how they compose.
• Simulate indicators on/off to preview conditional fields, constants, and attributes.
• A function-key legend (F3, F12, ...) shows every command key available to the record being previewed (file-level + record-level CAxx/CFxx); a key still shows even when its indicator condition isn't currently met (so you can see it's defined), switching to solid/inverted styling when it's actually active.
• An active ERRMSG() on a window shows on the window's own reserved message line (its last content row) when the window doesn't specify *NOMSGLIN, matching real DDS behavior, instead of always at the bottom of the physical screen.
• For files with more than one DSPSIZ format (e.g. *DS3/*DS4), switch which one is previewed — window positions/sizes and conditioned elements are resolved for the selected format. Dragging/resizing/centering a window, or adjusting a subfile's SFLPAG/SFLSIZ, only affects the size currently being previewed.
• The "Indicators" toggle and the selected display format persist when switching which record is previewed in the same panel.
• Stays in sync with the schema tree selection in both directions.
• "Focus" maximizes the preview so it fills the editing area, hiding the DDS source editor beside it; "Show code" brings the source back.
• Select a field or constant (or several, with Ctrl/Cmd+click) to get a "⋮ Actions" menu: add color/attribute, copy, or delete — applied to every selected element at once for a multi-selection (no per-element indicator prompts in that case).
• The decimal point and thousands-separator convention used to preview EDTCDE()-edited numeric fields — US or European — is configurable from the "⚙ Configuration" panel, either picked manually or fetched with one click from the connected IBM i's QDECFMT system value.

🧭 Schema navigation

• Two levels are shown: File and Records.
• Click on schema elements to jump directly to their location in the source.
• Right-click for context-aware actions.

File level

• View display file attributes (e.g., display size, command keys).
• Right-click options:
  • Create new records.
  • Assign command keys — a key number already used at the other level (file vs. record) is excluded, so you can't end up with the same key defined as both CA and CF.
  • Add Display Size: adds a second standard screen size (*DS3/*DS4) to a file that currently declares only one.

Records level

• Right-click options:
  • Create new records.
• Each record shows:
  • Record-level attributes.
  • Constants and fields.
• Right-click options on a record:
  • Add constant.
  • Add field.
  • Remove field.
  • Copy/Delete record.
  • Add "buttons" (constants for record commands).
  • Assign command keys — a key number already used at the other level (file vs. record) is excluded, so you can't end up with the same key defined as both CA and CF.
  • Add / Remove / Change indicators.
  • Resizing (if window record) — aware of every declared display size, resizing all of them at once.
  • Change Window Title (if window record) — targets the size being worked on when the record declares more than one.
  • Sort elements.
  • Preview Screen Layout (also available as an inline button on the record).

Constants

• Show text, position (row/column), indicators, and attributes.
• Right-click options:
  • Edit constant.
  • Copy constant (to the same or different record).
  • Remove constant.
  • Center constant on screen.
  • Change position (absolute position/relative to existing constant).
  • Apply colors/attributes.
  • Add / Remove / Change indicators, including more than 3 ANDed indicators (up to DDS's limit of 9, spilling onto continuation lines automatically) and OR'd conditions (add/remove whole OR'd groups, or edit indicators within one).
  • Fill constant with characters.

Fields

• Show name, length, type, position (row/column), and flags (referenced/hidden).
• Indicators and attributes are expandable; an OR'd condition is grouped into its ANDed sub-conditions ("Group 1 (AND)" / "OR" / "Group 2 (AND)" / ...) instead of one flat list. Hovering a conditioned field/constant/attribute shows the full condition (e.g. 51 AND NOT 61 AND 53 OR 52) as a tooltip.
• Right-click options:
  • Edit field.
  • Copy field (to the same or different record).
  • Remove field.
  • Center field on screen.
  • Change position (absolute position/relative to existing constant/field).
  • Apply colors/attributes.
  • Add validity checks.
  • Add editing keywords.
  • Add error messages.
  • Add / Remove / Change indicators, including more than 3 ANDed indicators (up to DDS's limit of 9, spilling onto continuation lines automatically) and OR'd conditions (add/remove whole OR'd groups, or edit indicators within one).
  • Resolve Referenced Field (for referenced fields only): fetches the real type/length/decimals from the connected IBM i, via the Code for i extension. Also available as "Resolve All Referenced Fields" from the status bar, for every pending referenced field in the document at once.

Attributes

• Add / Remove / Change indicators, with the same AND/OR support as fields and constants.
• Remove attribute.

🚀 How to Use

1. Open a DDS display file in VS Code.
2. Go to explorer view in VS Code.
3. The schema view will appear automatically with the name "DSPF STRUCTURE".
4. Use left-click to navigate, or right-click to access contextual options.

⚙️ Requirements

• Visual Studio Code v1.75 or higher.

🐞 Known Issues

No known blocking issues right now. Please open an issue if something isn't working as expected!

📝 To Do

• Bug fixes.
• Support removing a declared display size.
• Many new features to come!

📦 Version History

See the full changelog here.

Latest

1.2.0 - 2026-08-31

• Added: Preview's decimal point/thousands-separator convention for EDTCDE()-edited numeric fields (US/European) is now configurable from the "⚙ Configuration" panel, with a one-click "Fetch from IBM i" (reads the connected system's QDECFMT value) and a "Reset to Default" button.
• Fixed: an unedited numeric field (no EDTCDE/EDTWRD) didn't reserve the extra trailing position IBM i adds for the sign on an input-capable signed-numeric field — e.g. a 1,0 field showed as a single digit instead of digit + -, confirmed against real STRSDA.

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💬 Feedback is welcome! Please leave a comment, open an issue, and enjoy using DSPF-edit.