Fixes #23. Add null check.

.npmignore

@@ -13,3 +13,4 @@ tsconfig.json
 vendor/*/rationale.md
 eslint.config.js
 .ncurc
+.gitattributes

lib/index.js

@@ -113,7 +113,9 @@ const visit = peggy.compiler.visitor.build({
       }
     }
 
-    if (node.min.type === "constant" && !node.min.value) {
+    if (!node.min
+        || ((node.min.type === "constant")
+            && (node.min.value === 0))) {
       return new ZeroOrMore(
         visit(node.expression, context),
         { rep, min, max }

package.json

@@ -32,11 +32,11 @@
   },
   "devDependencies": {
     "@peggyjs/eslint-config": "^3.2.4",
-    "@peggyjs/eslint-plugin": "2.0.2",
-    "@types/node": "^20.11.21",
+    "@peggyjs/eslint-plugin": "2.1.0",
+    "@types/node": "^20.11.24",
     "@typescript-eslint/eslint-plugin": "^7.1.0",
     "@typescript-eslint/parser": "^7.1.0",
-    "ava": "^6.1.1",
+    "ava": "^6.1.2",
     "c8": "^9.1.0",
     "chokidar-cli": "^3.0.0",
     "eslint": "^8.57.0",

test/index.test.js

@@ -37,3 +37,9 @@ test("actions", t => {
 test("wrapCount", t => {
   t.is(wrapCount(null), null);
 });
+
+test("it handles single-value repeats", t => {
+  const diag = tracks({ text: "x = 'x'|2|" });
+  t.snapshot(diag.toStandalone());
+});
+

test/snapshots/index.test.js.md

@@ -0,0 +1,143 @@
+# Snapshot report for `test/index.test.js`
+
+The actual snapshot is saved in `index.test.js.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## it handles single-value repeats
+
+> Snapshot 1
+
+    `<svg class="railroad-diagram" width="256.5" height="153" viewBox="0 0 256.5 153" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">␊
+    <g transform="translate(.5 .5)">␊
+    <g class="Start">␊
+    <path d="M20 87v20m10 -20v20m-10 -10h20"></path>␊
+    </g>␊
+    <path d="M40 97h10"></path>␊
+    <g class="Group rule">␊
+    <path d="M50 97h0"></path>␊
+    <path d="M206.5 97h0"></path>␊
+    <rect x="50" y="36" width="156.5" height="97" rx="10" ry="10" class="group-box"></rect>␊
+    <g class="Choice">␊
+    <path d="M50 97h0"></path>␊
+    <path d="M206.5 97h0"></path>␊
+    <path d="M50 97a10 10 0 0 0 10 -10v-33a10 10 0 0 1 10 -10"></path>␊
+    <g class="Skip">␊
+    <path d="M70 44h116.5"></path>␊
+    </g>␊
+    <path d="M186.5 44a10 10 0 0 1 10 10v33a10 10 0 0 0 10 10"></path>␊
+    <path d="M50 97h20"></path>␊
+    <g class="Group repeat-box">␊
+    <path d="M70 97h0"></path>␊
+    <path d="M186.5 97h0"></path>␊
+    <rect x="70" y="68" width="116.5" height="57" rx="10" ry="10" class="group-box"></rect>␊
+    <g class="OneOrMore">␊
+    <path d="M70 97h46"></path>␊
+    <path d="M176.5 97h10"></path>␊
+    <g class="comment range">␊
+    <text x="92" y="89" class="comment">..</text>␊
+    </g>␊
+    <g class="comment">␊
+    <text x="107.5" y="89" class="comment">2</text>␊
+    </g>␊
+    <path d="M126 97a10 10 0 0 0 -10 10v0a10 10 0 0 0 10 10"></path>␊
+    <g class="Skip">␊
+    <path d="M126 117h40.5"></path>␊
+    </g>␊
+    <path d="M166.5 117a10 10 0 0 0 10 -10v0a10 10 0 0 0 -10 -10"></path>␊
+    <path d="M116 97h10"></path>␊
+    <path d="M166.5 97h10"></path>␊
+    <g class="terminal literal">␊
+    <path d="M126 97h-2.5"></path>␊
+    <path d="M169 97h-2.5"></path>␊
+    <rect x="123.5" y="86" width="45.5" height="22" rx="10" ry="10"></rect>␊
+    <text x="146.25" y="101">"x"</text>␊
+    </g>␊
+    </g>␊
+    <g class="comment">␊
+    <path d="M70 60h0"></path>␊
+    <path d="M122 60h0"></path>␊
+    <text x="96" y="65" class="comment">repeat</text>␊
+    </g>␊
+    </g>␊
+    <path d="M186.5 97h20"></path>␊
+    </g>␊
+    <g class="comment">␊
+    <path d="M50 28h0"></path>␊
+    <path d="M67 28h0"></path>␊
+    <text x="58.5" y="33" class="comment">x</text>␊
+    </g>␊
+    </g>␊
+    <path d="M206.5 97h10"></path>␊
+    <path class="End" d="M 216.5 97 h 20 m -10 -10 v 20 m 10 -20 v 20"></path>␊
+    </g>␊
+    <style>␊
+      svg {␊
+        background-color: hsl(30,20%,95%);␊
+      }␊
+      path {␊
+        stroke-width: 3;␊
+        stroke: black;␊
+        fill: rgba(0,0,0,0);␊
+      }␊
+      text {␊
+        font: bold 14px monospace;␊
+        text-anchor: middle;␊
+        white-space: pre;␊
+      }␊
+      text.diagram-text {␊
+        font-size: 12px;␊
+      }␊
+      text.diagram-arrow {␊
+        font-size: 16px;␊
+      }␊
+      text.label {␊
+        text-anchor: start;␊
+      }␊
+      text.comment {␊
+        font: italic 12px monospace;␊
+      }␊
+      g.non-terminal text {␊
+        /*font-style: italic;*/␊
+      }␊
+      rect {␊
+        stroke-width: 3;␊
+        stroke: black;␊
+        fill: hsl(120,100%,90%);␊
+      }␊
+      rect.group-box {␊
+        stroke: gray;␊
+        stroke-dasharray: 10 5;␊
+        fill: none;␊
+      }␊
+      path.diagram-text {␊
+        stroke-width: 3;␊
+        stroke: black;␊
+        fill: white;␊
+        cursor: help;␊
+      }␊
+      .decision path {␊
+        fill: #ccc;␊
+      }␊
+      g.diagram-text:hover path.diagram-text {␊
+        fill: #eee;␊
+      }␊
+      text.repeat-text {␊
+        font: italic 12px monospace;␊
+        text-anchor: end;␊
+      }␊
+      .repeat-box > rect.group-box {␊
+        stroke: gray;␊
+        stroke-width: 2;␊
+        stroke-dasharray: 1 5;␊
+        fill: none;␊
+      }␊
+      .delimiter > rect.group-box {␊
+        stroke: gray;␊
+        stroke-width: 2;␊
+        stroke-dasharray: 1 5;␊
+        fill: none;␊
+      }␊
+    </style>␊
+    </svg>␊
+    `