SWMM INP Inspector

SWMM INP Inspector is a VS Code extension for reading large Storm Water Management Model (.inp) files.

It adds section-aware context, table-friendly coloring, and identifier occurrence lookup so you can move around complex models quickly.

Feature overview

• Sticky section context: section headings like [CONDUITS] and their immediate ; header comments stay visible with Sticky Scroll.
• Section quick navigation: jump to any section from Command Palette.
• Rainbow columns: table-like rows are tokenized by column and colored by token index (text color only, no background fill).
• Peek occurrences on click: Ctrl/Cmd+click (Go to Definition) opens Peek with all in-file occurrences of the clicked identifier.

Tutorial video

If your client does not render embedded MP4, use one of these links:

• Watch on GitHub
• Direct MP4 URL

Quick start

1. Open a SWMM .inp file.
2. Confirm the language mode is SWMM INP.
3. Use SWMM INP: Go to Section from Command Palette.
4. Ctrl/Cmd+click an object ID to open a Peek list of all its in-file occurrences.

Commands

• SWMM INP: Go to Section
• SWMM INP: Refresh Rainbow Columns

Settings

• swmmInp.enableRainbowColumns (boolean, default true)
  Enable or disable rainbow token coloring.
• swmmInp.rainbowPalette (string[])
  Ordered list of text colors; column color is columnIndex % palette.length.

How the extension works

1) Section parsing and sticky context

• Sections are detected with [SECTION] heading lines.
• Each section range ends at the line before the next section heading.
• Consecutive ; comment lines immediately below a section heading are treated as header context.
• Document symbols are emitted as a nested tree: section symbol -> header comment symbols.
  This allows Sticky Scroll to pin both the section name and explanatory comment lines.

2) Rainbow column highlighting

• For normal data rows, tokens are split by whitespace while preserving quoted strings.
• For section header comment rows (for example ;;Name From Node To Node), tokens are split using 2+ spaces to keep multi-word labels together.
• Section headings, blank lines, and non-header comment lines are ignored.
• Decorations are refreshed on document edits, active editor changes, visible editor changes, and palette setting changes.

3) Identifier occurrence peek

The definition provider builds a per-document analysis cache that includes:

• parsed rows per line,
• section metadata,
• an identifier occurrence index (identifier -> all token locations in the document).

When you Ctrl/Cmd+click a token:

1. The provider identifies the token under cursor.
2. It normalizes the token key (case-insensitive, quote-aware).
3. It returns all matching locations from the occurrence index.
4. VS Code shows them in the Peek Definition panel (language defaults are configured to prefer peek).

Development (F5)

Press F5 and select Run SWMM INP Inspector to start an Extension Development Host window.

If VS Code prompts to debug Plain Text, open this project folder and select the extension-host launch profile in Run and Debug.

This project is licensed under the GNU General Public License v3.0 or later (GPL-3.0-or-later).
See the LICENSE file for the full license text.

Known limitations

• Peek results are purely token-based occurrences in the current file (not semantic model validation).
• Columns may not be colored properly if the section content is not a table or the number of space between headings is less than 2.
• Very common identifiers (if clicked) can produce large peek result lists.