Regex literals are enclosed in forward slashes and may contain zero
or more trailing flag characters. Interpretation of escape sequences
within regular expression literals is subject of the underlying
regular expression engine.

-- Expect stdout --
[ "/Hello world/", "/test/gis", "/test/g", "/test1 / test2/", "/1\n\\.\u0007\\bc☀\\\\/" ]
-- End --

-- Testcase --
{%
	print([
		/Hello world/,				// A very simple expression
		/test/gsi,					// Regular expression flags
		/test/gg,					// Repeated flags
		/test1 \/ test2/,			// Escaped forward slash
		/\x31\n\.\a\b\c\u2600\\/	// Ensure that escape sequences are passed as-is
	], "\n");
%}
-- End --


Testing regular expression type.

-- Expect stdout --
regexp
-- End --

-- Testcase --
{{ type(/foo/) }}
-- End --


Testing invalid flag characters.

-- Expect stderr --
Syntax error: Unexpected token
Expecting ';'
In line 2, byte 8:

 `    /test/x`
            ^-- Near here


-- End --

-- Testcase --
{%
	/test/x
%}
-- End --


Testing unclosed regular expression.

-- Expect stderr --
Syntax error: Unterminated string
In line 2, byte 2:

 `    /foo \/`
      ^-- Near here


-- End --

-- Testcase --
{%
	/foo \/
%}
-- End --


Testing regex compilation errors.

-- Expect stderr --
Catched syntax error
In line 7, byte 30:

 `            die("Catched syntax error");`
  Near here ----------------------------^


-- End --

-- Testcase --
{%
	try {
		/foo (/
	}
	catch (e) {
		if (e.type == "Syntax error")
			die("Catched syntax error");
	}
%}
-- End --


Testing that slashes within character classes are not treated as regex
literal delimitters.

-- Expect stdout --
[
	"/[/]/",
	"/[[./.]/]/",
	"/[[:alpha:]/]/",
	"/[[=/=]/]/"
]
-- End --

-- Testcase --
{%
	printf("%.J\n", [
		/[/]/,
		/[[./.]/]/,
		/[[:alpha:]/]/,
		/[[=/=]/]/
	]);
%}
-- End --


Testing that regex extension macros are substituted only outside of
bracket set expressions.

-- Expect stdout --
[
	"/ \\b \\B [\b B] /",
	"/ \\< \\> [< >] /",
	"/ [[:digit:]] [^[:digit:]] [d D] /",
	"/ [[:space:]] [^[:space:]] [s S] /",
	"/ [[:alnum:]_] [^[:alnum:]_] [w W] /"
]
-- End --

-- Testcase --
{%
	printf("%.J\n", [
		/ \b \B [\b \B] /,   // \b outside brackets is a word boundary,
		                     // \b within brackets is backspace
		/ \< \> [\< \>] /,
		/ \d \D [\d \D] /,
		/ \s \S [\s \S] /,
		/ \w \W [\w \W] /
	]);
%}
-- End --