Adding first operator

2026-09-05 00:54:51 +08:00 · 2025-09-10 18:47:52 +10:00
parent ff40a023cc
commit 4532346e13
6 changed files with 588 additions and 0 deletions
@@ -0,0 +1,184 @@
+package yqlib
+
+import "testing"
+
+var firstOperatorScenarios = []expressionScenario{
+	{
+		description: "First matching element from array",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with multiple matches",
+		document:    "[{a: banana},{a: cat},{a: apple},{a: cat}]",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with numeric condition",
+		document:    "[{a: 10},{a: 100},{a: 1}]",
+		expression:  `first(.a > 50)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: 100}\n",
+		},
+	},
+	{
+		description: "First matching element from array with boolean condition",
+		document:    "[{a: false},{a: true},{a: false}]",
+		expression:  `first(.a == true)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: true}\n",
+		},
+	},
+	{
+		description: "First matching element from array with null values",
+		document:    "[{a: null},{a: cat},{a: apple}]",
+		expression:  `first(.a != null)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with complex condition",
+		document:    "[{a: dog, b: 5},{a: cat, b: 3},{a: apple, b: 7}]",
+		expression:  `first(.b > 4)`,
+		expected: []string{
+			"D0, P[0], (!!map)::{a: dog, b: 5}\n",
+		},
+	},
+	{
+		description: "First matching element from map",
+		document:    "x: {a: banana}\ny: {a: cat}\nz: {a: apple}",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[y], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from map with numeric condition",
+		document:    "x: {a: 10}\ny: {a: 100}\nz: {a: 1}",
+		expression:  `first(.a > 50)`,
+		expected: []string{
+			"D0, P[y], (!!map)::{a: 100}\n",
+		},
+	},
+	{
+		description: "First matching element from nested structure",
+		document:    "items: [{a: banana},{a: cat},{a: apple}]",
+		expression:  `.items | first(.a == "cat")`,
+		expected: []string{
+			"D0, P[items 1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element with no matches",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a == "dog")`,
+		expected:    []string{
+			// No output expected when no matches
+		},
+	},
+	{
+		description: "First matching element from empty array",
+		document:    "[]",
+		expression:  `first(.a == "cat")`,
+		expected:    []string{
+			// No output expected when array is empty
+		},
+	},
+	{
+		description: "First matching element from scalar node",
+		document:    "hello",
+		expression:  `first(. == "hello")`,
+		expected:    []string{
+			// No output expected when node is scalar (no content to splat)
+		},
+	},
+	{
+		description: "First matching element from null node",
+		document:    "null",
+		expression:  `first(. == "hello")`,
+		expected:    []string{
+			// No output expected when node is null (no content to splat)
+		},
+	},
+	{
+		description: "First matching element with string condition",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a | test("^c"))`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element with length condition",
+		document:    "[{a: hi},{a: hello},{a: world}]",
+		expression:  `first(.a | length > 4)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: hello}\n",
+		},
+	},
+	{
+		description: "First matching element from array of strings",
+		document:    "[banana, cat, apple]",
+		expression:  `first(. == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!str)::cat\n",
+		},
+	},
+	{
+		description: "First matching element from array of numbers",
+		document:    "[10, 100, 1]",
+		expression:  `first(. > 50)`,
+		expected: []string{
+			"D0, P[1], (!!int)::100\n",
+		},
+	},
+	// New tests for no RHS (return first child)
+	{
+		description: "First element with no RHS from array",
+		document:    "[10, 100, 1]",
+		expression:  `first`,
+		expected: []string{
+			"D0, P[0], (!!int)::10\n",
+		},
+	},
+	{
+		description: "First element with no RHS from array of maps",
+		document:    "[{a: 10},{a: 100}]",
+		expression:  `first`,
+		expected: []string{
+			"D0, P[0], (!!map)::{a: 10}\n",
+		},
+	},
+	{
+		description: "No RHS on empty array returns nothing",
+		document:    "[]",
+		expression:  `first`,
+		expected:    []string{},
+	},
+	{
+		description: "No RHS on scalar returns nothing",
+		document:    "hello",
+		expression:  `first`,
+		expected:    []string{},
+	},
+	{
+		description: "No RHS on null returns nothing",
+		document:    "null",
+		expression:  `first`,
+		expected:    []string{},
+	},
+}
+
+func TestFirstOperatorScenarios(t *testing.T) {
+	for _, tt := range firstOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentOperatorScenarios(t, "first", firstOperatorScenarios)
+}