| // Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /// @assertion constantPattern ::= booleanLiteral |
| /// | nullLiteral |
| /// | '-'? numericLiteral |
| /// | stringLiteral |
| /// | symbolLiteral |
| /// | identifier |
| /// | qualifiedName |
| /// | constObjectExpression |
| /// | 'const' typeArguments? '[' elements? ']' |
| /// | 'const' typeArguments? '{' elements? '}' |
| /// | 'const' '(' expression ')' |
| /// |
| /// A constant pattern determines if the matched value is equal to the |
| /// constant's value. We don't allow all expressions here because many |
| /// expression forms syntactically overlap other kinds of patterns. We avoid |
| /// ambiguity while supporting terse forms of the most common constant |
| /// expressions like so: |
| /// ... |
| /// Named constants are also allowed because they aren't ambiguous. That |
| /// includes simple identifiers like someConstant, prefixed constants like |
| /// some_library.aConstant, static constants on classes like |
| /// SomeClass.aConstant, and prefixed static constants like |
| /// some_library.SomeClass.aConstant. Simple identifiers would be ambiguous with |
| /// variable patterns that aren't marked with var, final, or a type, but |
| /// unmarked variable patterns are only allowed in irrefutable contexts where |
| /// constant patterns are prohibited. |
| /// |
| /// @description Check named constants with a library prefix in constant |
| /// patterns. Test switch expression |
| /// @author sgrekhov22@gmail.com |
| |
| import "patterns_lib.dart" as p; |
| import "../../Utils/expect.dart"; |
| |
| String testBool(bool value) { |
| return switch (value) { |
| p.True => "true", |
| p.False => "false" |
| }; |
| } |
| |
| String testNum(num value) { |
| return switch (value) { |
| p.Zero => "zero", |
| p.Pi => "pi", |
| p.Answer => "answer", |
| p.Negative => "negative", |
| p.NegativePi => "negative-pi", |
| p.MaxJSInt => "max_int", |
| _ => "default" |
| }; |
| } |
| |
| String testString(String value) { |
| return switch (value) { |
| p.Melody => "Melody", |
| _ => "default" |
| }; |
| } |
| |
| main() { |
| Expect.equals("true", testBool(true)); |
| Expect.equals("false", testBool(false)); |
| |
| Expect.equals("zero", testNum(0)); |
| Expect.equals("zero", testNum(0.0)); |
| Expect.equals("pi", testNum(3.14)); |
| Expect.equals("answer", testNum(42)); |
| Expect.equals("negative", testNum(-1)); |
| Expect.equals("negative-pi", testNum(-3.14)); |
| Expect.equals("max_int", testNum(9007199254740991)); |
| Expect.equals("default", testNum(1)); |
| |
| Expect.equals("Melody", testString("Lily was here")); |
| Expect.equals("default", testString("")); |
| } |