Switch support for lsl preproc by WolfGangS · Pull Request #59 · secondlife/sl-vscode-plugin

WolfGangS · 2026-01-29T17:08:03Z

Add Switch statement support a la firestorm preprocessor

Closes #38

This also include a fairly large refactor to make most of the parsers lexers and processors, use 1 language config passed in from the top down, rather than each fetching their own copy.

I did this so that the config switch for enabling switch statements can be checked once at the start, and then have switch added to the lsl language config for that run.

Signed-off-by: WolfGangS <flamin2k8@gmail.com>

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Pull request overview

This PR adds switch statement preprocessing support for LSL scripts, converting switch(expr) { case v: { ... } default: { ... } } syntax into equivalent if/jump/label patterns compatible with LSL's execution model (matching Firestorm's preprocessor behavior). It also includes a significant refactor passing LanguageLexerConfig objects top-down instead of ScriptLanguage strings throughout the preprocessor pipeline.

Changes:

New switch directive handler in parser.ts that parses case blocks and emits LSL if/jump/@label equivalents, plus a deterministic RNG class for unique label generation.
API refactor across Parser, ConditionalProcessor, IncludeProcessor to accept LanguageLexerConfig instead of ScriptLanguage string; MacroProcessor constructor drops its language parameter; getLanguageConfig() now returns a structuredClone.
New configuration key PreprocessorLSLSwitchStatements, package.json setting, test workspace files, and comprehensive test updates across all test files.

Reviewed changes

Copilot reviewed 27 out of 27 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
`src/shared/parser.ts`	Core switch directive implementation, `RNG` class, `parseToken` refactor, new helper methods
`src/shared/lexer.ts`	Added `name` field to configs, split `LanguageLexerConfig`/`CustomLanguageLexerConfig`, `getLanguageConfig` uses `structuredClone`, removed overloaded constructor
`src/shared/lexingpreprocessor.ts`	Updated `process()` signature to accept `LanguageLexerConfig`
`src/shared/diagnostics.ts`	New `DiagnosticError` class for throw-based error propagation
`src/shared/macroprocessor.ts`	Removed language parameter from constructor
`src/shared/conditionalprocessor.ts`	Accepts `LanguageLexerConfig` instead of `ScriptLanguage`
`src/shared/includeprocessor.ts`	Accepts `LanguageLexerConfig` instead of `ScriptLanguage`
`src/scriptsync.ts`	New `getLanuageConfig()` helper that conditionally adds `switch` to directive keywords
`src/synchservice.ts`	Use `getLanguageConfig()` instead of direct `LANGUAGE_CONFIGS` access
`src/interfaces/configinterface.ts`	New `PreprocessorLSLSwitchStatements` config key
`package.json`	New VSCode setting for switch statement support
`src/test/suite/*.test.ts`	Updated all tests to use `getLanguageConfig()` for typed configs
`src/test/workspace/set_1/test_switch*.lsl`	Test input and expected output for switch preprocessing
`doc/preprocessor-guide.md`	Documentation for the new switch statement feature

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Copilot · 2026-03-04T17:43:38Z

src/shared/parser.ts

+                    break;
+                }
+            }
+            parser.parseToken(current);


parser.parseToken(current) is called without await at line 987, inside consumeCaseBlock. Since parseToken is async and may internally call await this.handleDirective(token), the Promise returned by parseToken is silently discarded. This means any async directives (e.g., #include) inside a case body will not be awaited, potentially leading to incorrect ordering, missing output, or unhandled errors. This call must be awaited: await parser.parseToken(current);.

Copilot · 2026-03-04T17:43:39Z

src/shared/parser.ts

+class RNG {
+    private state: number;
+    constructor(seed: number = 9863369152) {
+        // Ensure seed is treated as a 32-bit signed integer
+        this.state = seed | 0;
+    }
+    public next(): number {
+        // Xorshift* algorithm (32-bit integer arithmetic)
+        let x = this.state;
+        x ^= x << 13;
+        x ^= x >> 17;
+        x ^= x << 5;
+        // Clamp back to 32-bit signed integer
+        x |= 0;
+        this.state = x;
+        return x & 0x7FFFFFFF;
+    }
+
+    public nextHex(): string {
+        return this.next().toString(16).padStart(8, '0');
+    }
+}


The RNG class is declared outside the Parser class (after the closing } on line 2167) but before the //#endregion marker. While this works as a module-private class in TypeScript, the RNG class is logically an implementation detail of ParserState/Parser and is declared in an awkward location between the Parser class body and its #endregion comment. It should either be moved inside the module scope before the Parser class or be a proper private inner implementation. Additionally, the checkTokenOfType method and peek method added in this PR are never called anywhere in the codebase — they are dead code that should be removed or used.

Copilot · 2026-03-04T17:43:39Z

src/test/suite/lexingpreprocessor.test.ts

+        console.error("======RESULT CONTENT======");
+        console.error(result.content);
+        console.error("======END RESULT CONTENT======");
+


There are two leftover debug console.error statements at lines 1678-1680 of the test file that print ======RESULT CONTENT====== and the full result content on every test run. These should be removed before merging.

Suggested change

console.error("======RESULT CONTENT======");

console.error(result.content);

console.error("======END RESULT CONTENT======");

Copilot · 2026-03-04T17:43:40Z

src/test/suite/parser-diagnostics.test.ts

+import { getLanguageConfig, Lexer } from '../../shared/lexer';
 import { DiagnosticCollector, DiagnosticSeverity, ErrorCodes } from '../../shared/diagnostics';
 import { normalizePath, NormalizedPath } from '../../interfaces/hostinterface';
+import { get } from 'http';


There is an unused import import { get } from 'http'; on line 11. This appears to be an accidental leftover that should be removed.

Suggested change

import { get } from 'http';

Copilot · 2026-03-04T17:43:40Z

src/test/suite/lexingpreprocessor.test.ts

        });
    });
+
+    test('should allow switch as identifier if switch statments not enabled for lsl preproc', async () => {


Spelling error: "statments" should be "statements" in the test name 'should allow switch as identifier if switch statments not enabled for lsl preproc'. This same misspelling also appears in the duplicate test name at line 1642.

Copilot · 2026-03-04T17:43:40Z

src/shared/parser.ts

    /** Require state (for SLua require() directives) - only present when require is supported */
    requireState?: RequireState;
+    /** Set of unique identifiers to use for naming things like switch/loop jumps */
+    uniqueidentifiers: Set<string>;


The uniqueidentifiers field in ParserState uses a lowercase 'i' with no separator, while the rest of the codebase uses camelCase for multi-word identifiers (e.g., requireState, includeState). The field name should be uniqueIdentifiers (camelCase) to match the established naming convention.

Suggested change

uniqueidentifiers: Set<string>;

uniqueIdentifiers: Set<string>;

Copilot · 2026-03-04T17:43:41Z

src/scriptsync.ts

        return finalContent;
    }

+    private getLanuageConfig(): LanguageLexerConfig {


The method getLanuageConfig is a typo — it should be getLanguageConfig (missing 'g' in 'Language'). This typo appears in both the method name definition and all three call sites in scriptsync.ts.

Suggested change

private getLanuageConfig(): LanguageLexerConfig {

private getLanguageConfig(): LanguageLexerConfig {

Copilot · 2026-03-04T17:43:41Z

src/scriptsync.ts


            this.macros.clearNonSystemMacros();
+            const languageConfig = this.getLanuageConfig();
+            console.error("LANG CONFIG", languageConfig);


There is a leftover debug console.error("LANG CONFIG", languageConfig) statement at line 402 that logs the full language config object to stderr on every preprocessing run. This should be removed before merging.

Suggested change

console.error("LANG CONFIG", languageConfig);

Copilot · 2026-03-04T17:43:41Z

src/test/suite/lexingpreprocessor.test.ts

+        assert.strictEqual(result.issues.length, 1, 'Should have 1 issue');
+    });
+
+    test('should allow switch as identifier if switch statments not enabled for lsl preproc', async () => {


The test at line 1642 has the wrong name: it is titled 'should allow switch as identifier if switch statments not enabled for lsl preproc' but its body actually tests the opposite behavior — that switch is processed as a statement when lslLanguageConfigWithSwitch is used. This is a duplicate name of the test at line 1598, and the name does not match the intent of the test. The name should reflect that switch statements are correctly expanded when switch support is enabled.

Suggested change

test('should allow switch as identifier if switch statments not enabled for lsl preproc', async () => {

test('should expand switch statement when switch statements enabled for lsl preproc', async () => {

Copilot · 2026-03-04T17:43:42Z

src/test/suite/require-table.test.ts

-import { Lexer } from '../../shared/lexer';
+import { getLanguageConfig, Lexer } from '../../shared/lexer';
 import { HostInterface, NormalizedPath, normalizePath } from '../../interfaces/hostinterface';
+import { get } from 'http';


There is an unused import import { get } from 'http'; on line 18. This appears to be an accidental leftover that should be removed.

Suggested change

import { get } from 'http';

Switch support for lsl preproc

076fc25

Signed-off-by: WolfGangS <flamin2k8@gmail.com>

WolfGangS mentioned this pull request Jan 29, 2026

Add variadic function macro support #60

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Rider-Linden requested a review from Copilot March 4, 2026 17:38

Copilot started reviewing on behalf of Rider-Linden March 4, 2026 17:39 View session

Copilot AI reviewed Mar 4, 2026

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Switch support for lsl preproc#59

Switch support for lsl preproc#59
WolfGangS wants to merge 1 commit intosecondlife:developfrom
WolfGangS:feature/lsl-switch

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	uniqueidentifiers: Set<string>;
	uniqueIdentifiers: Set<string>;

	private getLanuageConfig(): LanguageLexerConfig {
	private getLanguageConfig(): LanguageLexerConfig {

	test('should allow switch as identifier if switch statments not enabled for lsl preproc', async () => {
	test('should expand switch statement when switch statements enabled for lsl preproc', async () => {

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