From fcb7bd4a61bd8614652a94b842b6d261ff8403a7 Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Mon, 24 Jan 2022 19:38:34 +0530
Subject: feat(eval): adds min-max quantifier evaluation

---
 src/eval/index.ts   | 17 +++++++++++++++++
 tests/basic.spec.ts | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/src/eval/index.ts b/src/eval/index.ts
index ed757e7..96ccbef 100644
--- a/src/eval/index.ts
+++ b/src/eval/index.ts
@@ -108,6 +108,23 @@ const checkExpr = <T>(
         )
       },
 
+      MinMax: ({ expr, min, max }) => {
+        const { localSkip, getSkips } = accumulateSkip()
+        const result = checkExpr(Expr.ZeroOrMore({ expr }), item, list, index, localSkip)
+        // TODO: Use nested skips
+
+        const matches = result[0].value.length
+        const capturedMatchCount = matches < min ? 0 : Math.min(matches, max)
+        // const skipCount = getSkips().reduce((a, b) => a + b, 0)
+
+        return pipe(
+          result
+            .map(r => ({ ...r, value: r.value.slice(0, capturedMatchCount) }))
+            .filter(r => r.value.length > 0),
+          skip(capturedMatchCount || 1),
+        )
+      },
+
       ZeroOrMore: ({ expr }) => {
         // TODO: Nested quantified expressions?
         const matches = pipe(
diff --git a/tests/basic.spec.ts b/tests/basic.spec.ts
index 33a4228..db074d4 100644
--- a/tests/basic.spec.ts
+++ b/tests/basic.spec.ts
@@ -198,5 +198,46 @@ describe('Basic tests', () => {
         },
       ])
     })
+
+    it('should match min-max quantified expressions', () => {
+      expect(
+        matchAll(/[age \n]{2, 4}/, [
+          {},
+          { age: 1 },
+          '',
+        ]).groups,
+      ).toEqual([])
+
+      expect(
+        matchAll(/[age \n]{2, 4}/, [
+          {},
+          { age: 1 },
+          { age: 0 },
+          '',
+        ]).groups,
+      ).toEqual([{ value: [{ age: 1 }, { age: 0 }], index: 1 }])
+
+      expect(
+        matchAll(/[age \n]{2, 4}/, [
+          {},
+          { age: 1 },
+          { age: 2 },
+          { age: 0 },
+          '',
+        ]).groups,
+      ).toEqual([{ value: [{ age: 1 }, { age: 2 }, { age: 0 }], index: 1 }])
+
+      expect(
+        matchAll(/[age \n]{2, 4}/, [
+          {},
+          { age: 1 },
+          { age: 2 },
+          { age: 0 },
+          { age: 8 },
+          { age: 4 },
+          '',
+        ]).groups,
+      ).toEqual([{ value: [{ age: 1 }, { age: 2 }, { age: 0 }, { age: 8 }], index: 1 }])
+    })
   })
 })
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