add lint rule for multiline if/else consistency

src/lint/collect-algorithm-diagnostics.ts

@@ -1,4 +1,4 @@
-import type { Node as EcmarkdownNode, OrderedListItemNode } from 'ecmarkdown';
+import type { Node as EcmarkdownNode, OrderedListItemNode, OrderedListNode } from 'ecmarkdown';
 
 import type { LintingError, Reporter } from './algorithm-error-reporter-type';
 import type { default as Spec, Warning } from '../Spec';
@@ -11,21 +11,24 @@ import lintAlgorithmStepNumbering from './rules/algorithm-step-numbering';
 import lintAlgorithmStepLabels from './rules/algorithm-step-labels';
 import lintForEachElement from './rules/for-each-element';
 import lintStepAttributes from './rules/step-attributes';
+import lintIfElseConsistency from './rules/if-else-consistency';
 import { checkVariableUsage } from './rules/variable-use-def';
 import { parse, Seq } from '../expr-parser';
 
 type LineRule = (
  report: Reporter,
  step: OrderedListItemNode,
  algorithmSource: string,
- parsedSteps: Map<OrderedListItemNode, Seq>
+ parsedSteps: Map<OrderedListItemNode, Seq>,
+ parent: OrderedListNode
 ) => void;
 const stepRules: LineRule[] = [
  lintAlgorithmLineStyle,
  lintAlgorithmStepNumbering,
  lintAlgorithmStepLabels,
  lintForEachElement,
  lintStepAttributes,
+ lintIfElseConsistency,
 ];
 
 export function collectAlgorithmDiagnostics(
@@ -84,13 +87,13 @@ export function collectAlgorithmDiagnostics(
  }
  }
 
- function applyRule(visit: LineRule, step: OrderedListItemNode) {
+ function applyRule(visit: LineRule, step: OrderedListItemNode, parent: OrderedListNode) {
  // we don't know the names of ops at this point
  // TODO maybe run later in the process? but not worth worrying about for now
- visit(reporter, step, algorithmSource, parsedSteps);
+ visit(reporter, step, algorithmSource, parsedSteps, parent);
  if (step.sublist?.name === 'ol') {
  for (const substep of step.sublist.contents) {
- applyRule(visit, substep);
+ applyRule(visit, substep, step.sublist);
  }
  }
  }
@@ -101,7 +104,7 @@ export function collectAlgorithmDiagnostics(
 
  for (const rule of stepRules) {
  for (const step of tree.contents.contents) {
- applyRule(rule, step);
+ applyRule(rule, step, tree.contents);
  }
  }
  if (allNodesParsedSuccessfully) {

src/lint/rules/if-else-consistency.ts

@@ -0,0 +1,57 @@
+import type { Reporter } from '../algorithm-error-reporter-type';
+import type { Seq } from '../../expr-parser';
+import type { OrderedListItemNode, OrderedListNode } from 'ecmarkdown';
+import { offsetToLineAndColumn } from '../../utils';
+
+const ruleId = 'if-else-consistency';
+
+/*
+Checks that `if`/`else` statements are both single-line or both multi-line.
+*/
+export default function (
+ report: Reporter,
+ step: OrderedListItemNode,
+ algorithmSource: string,
+ parsedSteps: Map<OrderedListItemNode, Seq>,
+ parent: OrderedListNode
+) {
+ const stepSeq = parsedSteps.get(step);
+ if (stepSeq == null) {
+ return;
+ }
+ const firstSeqItem = stepSeq.items[0];
+ if (firstSeqItem?.name !== 'text' || !/^(?:If|Else if)\b/.test(firstSeqItem.contents)) {
+ return;
+ }
+ const idx = parent.contents.indexOf(step);
+ if (idx >= parent.contents.length - 1) {
+ return;
+ }
+ const nextStep = parent.contents[idx + 1];
+ const nextSeq = parsedSteps.get(nextStep);
+ if (nextSeq == null) {
+ return;
+ }
+ const nextFirstSeqitem = nextSeq.items[0];
+ if (
+ nextFirstSeqitem?.name !== 'text' ||
+ !/^(?:Else|Otherwise)\b/.test(nextFirstSeqitem.contents)
+ ) {
+ return;
+ }
+ if (step.sublist != null && nextStep.sublist == null) {
+ const location = offsetToLineAndColumn(algorithmSource, nextFirstSeqitem.location.start.offset);
+ report({
+ ruleId,
+ ...location,
+ message: '"Else" steps should be multiline whenever their corresponding "If" is',
+ });
+ } else if (step.sublist == null && nextStep.sublist != null) {
+ const location = offsetToLineAndColumn(algorithmSource, firstSeqItem.location.start.offset);
+ report({
+ ruleId,
+ ...location,
+ message: '"If" steps should be multiline whenever their corresponding "Else" is',
+ });
+ }
+}

test/lint-algorithms.js

@@ -467,4 +467,132 @@ describe('linting algorithms', () => {
  `);
  });
  });
+
+ describe('if/else consistency', () => {
+ const ruleId = 'if-else-consistency';
+ it('rejects single-line if with multiline else', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. ${M}If some condition holds, do something.
+ 1. Else,
+ 1. Do something else.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"If" steps should be multiline whenever their corresponding "Else" is',
+ }
+ );
+ });
+
+ it('rejects single-line if with multiline else-if', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. ${M}If some condition holds, do something.
+ 1. Else if another condition holds, then
+ 1. Do something else.
+ 1. Else,
+ 1. Do something yet otherwise.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"If" steps should be multiline whenever their corresponding "Else" is',
+ }
+ );
+ });
+
+ it('rejects single-line else-if with multiline else', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. If some condition holds, do something.
+ 1. ${M}Else if another condition holds, do something else.
+ 1. Else,
+ 1. Do something yet otherwise.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"If" steps should be multiline whenever their corresponding "Else" is',
+ }
+ );
+ });
+
+ it('rejects multi-line if with single-line else', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. If some condition holds, then
+ 1. Do something.
+ 1. ${M}Else do something else.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"Else" steps should be multiline whenever their corresponding "If" is',
+ }
+ );
+ });
+
+ it('rejects multi-line if with single-line else-f', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. If some condition holds, then
+ 1. Do something.
+ 1. ${M}Else if another condition holds do something else.
+ 1. Else, do something yet otherwise.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"Else" steps should be multiline whenever their corresponding "If" is',
+ }
+ );
+ });
+
+ it('rejects multi-line else-if with single-line else', async () => {
+ await assertLint(
+ positioned`
+ <emu-alg>
+ 1. If some condition holds, then
+ 1. Do something.
+ 1. Else if another condition holds, then
+ 1. Do something else.
+ 1. ${M}Else, do something yet otherwise.
+ </emu-alg>`,
+ {
+ ruleId,
+ nodeType,
+ message: '"Else" steps should be multiline whenever their corresponding "If" is',
+ }
+ );
+ });
+
+ it('negative', async () => {
+ await assertLintFree(`
+ <emu-alg>
+ 1. If some condition holds, do something simple.
+ 1. Else, do something yet otherwise simple.
+ 1. If some condition holds, do something simple.
+ 1. Else if another condition holds, do something else simple.
+ 1. Else, do something yet otherwise simple.
+ 1. NOTE: Also works for multiline.
+ 1. If some condition holds, then
+ 1. Do something simple.
+ 1. Else,
+ 1. Do something yet otherwise simple.
+ 1. If some condition holds, then
+ 1. Do something simple.
+ 1. Else if another condition holds, then
+ 1. Do something else simple.
+ 1. Else,
+ 1. Do something yet otherwise simple.
+ </emu-alg>
+ `);
+ });
+ });
 });