zclsyntax: "Did you mean ...?" helper function

zcl/zclsyntax/didyoumean.go

@@ -0,0 +1,24 @@
+package zclsyntax
+
+import (
+	"github.com/agext/levenshtein"
+)
+
+// nameSuggestion tries to find a name from the given slice of suggested names
+// that is close to the given name and returns it if found. If no suggestion
+// is close enough, returns the empty string.
+//
+// The suggestions are tried in order, so earlier suggestions take precedence
+// if the given string is similar to two or more suggestions.
+//
+// This function is intended to be used with a relatively-small number of
+// suggestions. It's not optimized for hundreds or thousands of them.
+func nameSuggestion(given string, suggestions []string) string {
+	for _, suggestion := range suggestions {
+		dist := levenshtein.Distance(given, suggestion, nil)
+		if dist < 3 { // threshold determined experimentally
+			return suggestion
+		}
+	}
+	return ""
+}

zcl/zclsyntax/didyoumean_test.go

@@ -0,0 +1,51 @@
+package zclsyntax
+
+import "testing"
+
+func TestNameSuggestion(t *testing.T) {
+	var keywords = []string{"false", "true", "null"}
+
+	tests := []struct {
+		Input, Want string
+	}{
+		{"true", "true"},
+		{"false", "false"},
+		{"null", "null"},
+		{"bananas", ""},
+		{"NaN", ""},
+		{"Inf", ""},
+		{"Infinity", ""},
+		{"void", ""},
+		{"undefined", ""},
+
+		{"ture", "true"},
+		{"tru", "true"},
+		{"tre", "true"},
+		{"treu", "true"},
+		{"rtue", "true"},
+
+		{"flase", "false"},
+		{"fales", "false"},
+		{"flse", "false"},
+		{"fasle", "false"},
+		{"fasel", "false"},
+		{"flue", "false"},
+
+		{"nil", "null"},
+		{"nul", "null"},
+		{"unll", "null"},
+		{"nll", "null"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.Input, func(t *testing.T) {
+			got := nameSuggestion(test.Input, keywords)
+			if got != test.Want {
+				t.Errorf(
+					"wrong result\ninput: %q\ngot:   %q\nwant:  %q",
+					test.Input, got, test.Want,
+				)
+			}
+		})
+	}
+}