added start of CSS support

a-h · Jun 12, 2021 · 008a433 · 008a433
1 parent b7cfe4b
commit 008a433
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Showing 6 changed files with 744 additions and 22 deletions.
diff --git a/cssparser.go b/cssparser.go
@@ -0,0 +1,264 @@
+package templ
+
+import (
+	"io"
+
+	"github.com/a-h/lexical/parse"
+)
+
+// CSS.
+
+// CSS Parser.
+
+func newCSSParser() cssParser {
+	return cssParser{}
+}
+
+type cssParser struct {
+}
+
+var endCssParser = parse.String("{% endcss %}") // {% endcss %}
+
+func (p cssParser) Parse(pi parse.Input) parse.Result {
+	r := CSSExpression{
+		Properties: []CSSProperty{},
+	}
+
+	// Parse the name.
+	pr := newCSSExpressionParser().Parse(pi)
+	if !pr.Success {
+		return pr
+	}
+	r.Name = pr.Item.(cssExpression).Name
+
+	var from Position
+	for {
+		var pr parse.Result
+		from = NewPositionFromInput(pi)
+
+		// Try for an expression CSS declaration.
+		// background-color: {%= constants.BackgroundColor %};
+		pr = newExpressionCSSPropertyParser().Parse(pi)
+		if pr.Error != nil {
+			return pr
+		}
+		if pr.Success {
+			r.Properties = append(r.Properties, pr.Item.(CSSProperty))
+			continue
+		}
+
+		// Try for a constant CSS declaration.
+		// color: #ffffff;
+		pr = newConstantCSSPropertyParser().Parse(pi)
+		if pr.Error != nil {
+			return pr
+		}
+		if pr.Success {
+			r.Properties = append(r.Properties, pr.Item.(CSSProperty))
+			continue
+		}
+
+		// Eat any whitespace.
+		pr = optionalWhitespaceParser(pi)
+		if pr.Error != nil {
+			return pr
+		}
+		// {% endcss %}
+		from = NewPositionFromInput(pi)
+		if endCssParser(pi).Success {
+			return parse.Success("css", r, nil)
+		}
+		return parse.Failure("css", newParseError("expected {% endcss %} not found", from, NewPositionFromInput(pi)))
+	}
+}
+
+// {% css Func() %}
+type cssExpression struct {
+	Name Expression
+}
+
+func newCSSExpressionParser() cssExpressionParser {
+	return cssExpressionParser{}
+}
+
+type cssExpressionParser struct {
+}
+
+var cssExpressionNameParser = parse.All(parse.WithStringConcatCombiner,
+	parse.Letter,
+	parse.Many(parse.WithStringConcatCombiner, 0, 1000, parse.Any(parse.Letter, parse.ZeroToNine)),
+)
+
+func (p cssExpressionParser) Parse(pi parse.Input) parse.Result {
+	var r cssExpression
+
+	// Check the prefix first.
+	prefixResult := parse.String("{% css ")(pi)
+	if !prefixResult.Success {
+		return prefixResult
+	}
+
+	// Once we have the prefix, we must have a name and parameters.
+	// Read the name of the function.
+	from := NewPositionFromInput(pi)
+	pr := cssExpressionNameParser(pi)
+	if pr.Error != nil && pr.Error != io.EOF {
+		return pr
+	}
+	// If there's no match, the name wasn't correctly terminated.
+	if !pr.Success {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: invalid name", from, NewPositionFromInput(pi)))
+	}
+	to := NewPositionFromInput(pi)
+	r.Name = NewExpression(pr.Item.(string), from, to)
+	from = to
+
+	// Eat the open bracket.
+	if lb := parse.Rune('(')(pi); !lb.Success {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: parameters missing open bracket", from, NewPositionFromInput(pi)))
+	}
+
+	// Check there's no parameters.
+	from = NewPositionFromInput(pi)
+	pr = parse.StringUntil(parse.Rune(')'))(pi)
+	if pr.Error != nil && pr.Error != io.EOF {
+		return pr
+	}
+	// If there's no match, the name wasn't correctly terminated.
+	if !pr.Success {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: parameters missing close bracket", from, NewPositionFromInput(pi)))
+	}
+	if len(pr.Item.(string)) > 1 {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: found unexpected parameters", from, NewPositionFromInput(pi)))
+	}
+
+	// Eat ") %}".
+	from = NewPositionFromInput(pi)
+	if lb := parse.String(") %}")(pi); !lb.Success {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: unterminated (missing ' %}')", from, NewPositionFromInput(pi)))
+	}
+
+	// Expect a newline.
+	from = NewPositionFromInput(pi)
+	if lb := newLine(pi); !lb.Success {
+		return parse.Failure("cssExpressionParser", newParseError("css expression: missing terminating newline", from, NewPositionFromInput(pi)))
+	}
+
+	return parse.Success("cssExpressionParser", r, nil)
+}
+
+// CSS property name parser.
+var cssPropertyNameFirst = "abcdefghijklmnopqrstuvwxyz"
+var cssPropertyNameSubsequent = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-"
+var cssPropertyNameParser = parse.Then(parse.WithStringConcatCombiner,
+	parse.RuneIn(cssPropertyNameFirst),
+	parse.Many(parse.WithStringConcatCombiner, 0, 128, parse.RuneIn(cssPropertyNameSubsequent)),
+)
+
+// background-color: {%= constants.BackgroundColor %};
+func newExpressionCSSPropertyParser() expressionCSSPropertyParser {
+	return expressionCSSPropertyParser{}
+}
+
+type expressionCSSPropertyParser struct {
+}
+
+func (p expressionCSSPropertyParser) Parse(pi parse.Input) parse.Result {
+	var r ExpressionCSSProperty
+	var pr parse.Result
+	start := pi.Index()
+
+	// Optional whitespace.
+	if pr = optionalWhitespaceParser(pi); pr.Error != nil {
+		return pr
+	}
+	// Property name.
+	if pr = cssPropertyNameParser(pi); !pr.Success {
+		rewind(pi, start)
+		return pr
+	}
+	r.Name = pr.Item.(string)
+	// <space>:<space>
+	pr = parse.All(parse.WithStringConcatCombiner,
+		optionalWhitespaceParser,
+		parse.Rune(':'),
+		optionalWhitespaceParser)(pi)
+	if !pr.Success {
+		rewind(pi, start)
+		return pr
+	}
+
+	// {%= string %}
+	pr = newStringExpressionParser().Parse(pi)
+	if !pr.Success {
+		rewind(pi, start)
+		return pr
+	}
+	r.Value = pr.Item.(StringExpression)
+
+	// ;
+	from := NewPositionFromInput(pi)
+	if pr = parse.String(";")(pi); !pr.Success {
+		return parse.Failure("expression css declaration", newParseError("missing expected semicolon (;)", from, NewPositionFromInput(pi)))
+	}
+	// \n
+	from = NewPositionFromInput(pi)
+	if pr = parse.String("\n")(pi); !pr.Success {
+		return parse.Failure("expression css declaration", newParseError("missing expected linebreak", from, NewPositionFromInput(pi)))
+	}
+
+	return parse.Success("expression css declaration", r, nil)
+}
+
+// background-color: #ffffff;
+func newConstantCSSPropertyParser() constantCSSPropertyParser {
+	return constantCSSPropertyParser{}
+}
+
+type constantCSSPropertyParser struct {
+}
+
+func (p constantCSSPropertyParser) Parse(pi parse.Input) parse.Result {
+	var r ConstantCSSProperty
+	var pr parse.Result
+	start := pi.Index()
+
+	// Optional whitespace.
+	if pr = optionalWhitespaceParser(pi); pr.Error != nil {
+		return pr
+	}
+	// Property name.
+	if pr = cssPropertyNameParser(pi); !pr.Success {
+		rewind(pi, start)
+		return pr
+	}
+	r.Name = pr.Item.(string)
+	// <space>:<space>
+	pr = parse.All(parse.WithStringConcatCombiner,
+		optionalWhitespaceParser,
+		parse.Rune(':'),
+		optionalWhitespaceParser)(pi)
+	if !pr.Success {
+		rewind(pi, start)
+		return pr
+	}
+
+	// Everything until ';\n'
+	from := NewPositionFromInput(pi)
+	untilEnd := parse.All(parse.WithStringConcatCombiner,
+		optionalWhitespaceParser,
+		parse.String(";\n"),
+	)
+	pr = parse.StringUntil(untilEnd)(pi)
+	if !pr.Success {
+		return parse.Failure("constant css declaration", newParseError("missing expected semicolon and linebreak (;\\n)", from, NewPositionFromInput(pi)))
+	}
+	r.Value = pr.Item.(string)
+	// Chomp the ;\n
+	pr = untilEnd(pi)
+	if !pr.Success {
+		return parse.Failure("constant css declaration", newParseError("failed to chomp semicolon and linebreak (;\\n)", from, NewPositionFromInput(pi)))
+	}
+
+	return parse.Success("constant css declaration", r, nil)
+}