Mihaela Mihaljevic
951b808f02
Add the PureXML.Regex namespace: a recursive-descent parser for the XSD
regex grammar (literals, ., character classes with ranges and negation, the
\d \w \s family and negations, single-char escapes, grouping, alternation,
and the ?, *, +, {n}, {n,}, {n,m} quantifiers) compiled to a Thompson NFA.
matches(_:) is whole-string as xs:pattern requires, and runs linear in the
input with no backtracking blow-up. \p{...} category escapes are not yet
supported.
Closes #59
Closes #60
Closes #30
87 lines
3.0 KiB
Swift
87 lines
3.0 KiB
Swift
@testable import PureXML
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import Testing
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@Suite("Regex")
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struct RegexTests {
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private func matches(_ pattern: String, _ string: String) throws -> Bool {
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try PureXML.Regex.matches(pattern, string)
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}
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@Test("Literal patterns match the whole string")
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func test_literal() throws {
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#expect(try matches("abc", "abc"))
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#expect(try !matches("abc", "abcd"))
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#expect(try !matches("abc", "ab"))
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}
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@Test("The dot matches any character except line breaks")
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func test_dot() throws {
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#expect(try matches("a.c", "axc"))
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#expect(try !matches("a.c", "a\nc"))
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}
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@Test("Quantifiers ? * + bound repetition")
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func test_quantifiers() throws {
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#expect(try matches("ab?c", "ac"))
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#expect(try matches("ab?c", "abc"))
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#expect(try matches("ab*c", "abbbc"))
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#expect(try matches("ab+c", "abc"))
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#expect(try !matches("ab+c", "ac"))
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}
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@Test("Bounded quantifiers {n}, {n,}, {n,m}")
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func test_boundedQuantifiers() throws {
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#expect(try matches("a{3}", "aaa"))
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#expect(try !matches("a{3}", "aa"))
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#expect(try matches("a{2,}", "aaaa"))
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#expect(try matches("a{2,4}", "aaa"))
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#expect(try !matches("a{2,4}", "aaaaa"))
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}
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@Test("Alternation and grouping")
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func test_alternationGrouping() throws {
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#expect(try matches("cat|dog", "dog"))
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#expect(try matches("(ab)+", "ababab"))
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#expect(try matches("gr(a|e)y", "grey"))
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#expect(try !matches("gr(a|e)y", "groy"))
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}
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@Test("Character classes with ranges and negation")
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func test_charClasses() throws {
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#expect(try matches("[a-z]+", "hello"))
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#expect(try !matches("[a-z]+", "Hello"))
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#expect(try matches("[^0-9]+", "abc"))
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#expect(try matches("[abc]{2}", "ca"))
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}
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@Test("Class escapes \\d \\w \\s and their negations")
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func test_classEscapes() throws {
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#expect(try matches("\\d{4}", "2026"))
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#expect(try !matches("\\d{4}", "20x6"))
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#expect(try matches("\\w+", "a_1"))
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#expect(try matches("a\\sb", "a b"))
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#expect(try matches("\\D+", "abc"))
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}
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@Test("Escaped metacharacters are literal")
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func test_escapes() throws {
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#expect(try matches("a\\.b", "a.b"))
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#expect(try !matches("a\\.b", "axb"))
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#expect(try matches("\\(\\)", "()"))
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}
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@Test("A realistic ISBN-like pattern")
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func test_realistic() throws {
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let pattern = "\\d{3}-\\d{1,5}-\\d{1,7}-\\d{1,6}-[0-9X]"
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#expect(try matches(pattern, "978-0-13-468599-1"))
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#expect(try !matches(pattern, "abc-0-13-468599-1"))
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}
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@Test("Malformed patterns are rejected")
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func test_errors() {
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#expect(throws: PureXML.Regex.RegexError.self) { _ = try PureXML.Regex.Pattern("a(b") }
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#expect(throws: PureXML.Regex.RegexError.self) { _ = try PureXML.Regex.Pattern("*ab") }
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#expect(throws: PureXML.Regex.RegexError.self) { _ = try PureXML.Regex.Pattern("") }
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}
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}
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