101 lines
2.7 KiB
Go
101 lines
2.7 KiB
Go
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package parser
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import (
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"github.com/a-h/parse"
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"github.com/a-h/templ/parser/v2/goexpression"
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)
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var conditionalAttribute parse.Parser[ConditionalAttribute] = conditionalAttributeParser{}
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type conditionalAttributeParser struct{}
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func (conditionalAttributeParser) Parse(pi *parse.Input) (r ConditionalAttribute, ok bool, err error) {
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start := pi.Index()
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// Strip leading whitespace and look for `if `.
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if _, _, err = parse.OptionalWhitespace.Parse(pi); err != nil {
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return
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}
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if !peekPrefix(pi, "if ") {
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pi.Seek(start)
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return
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}
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// Parse the Go if expression.
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if r.Expression, err = parseGo("if attribute", pi, goexpression.If); err != nil {
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return
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}
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// Eat " {\n".
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if _, ok, err = openBraceWithOptionalPadding.Parse(pi); err != nil || !ok {
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err = parse.Error("attribute if: unterminated (missing closing '{\n')", pi.PositionAt(start))
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return
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}
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if _, _, err = parse.OptionalWhitespace.Parse(pi); err != nil {
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return
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}
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// Read the 'Then' attributes.
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// If there's no match, there's a problem reading the attributes.
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if r.Then, ok, err = (attributesParser{}).Parse(pi); err != nil || !ok {
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err = parse.Error("attribute if: expected attributes in block, but none were found", pi.Position())
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return
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}
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if len(r.Then) == 0 {
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err = parse.Error("attribute if: invalid content or no attributes were found in the if block", pi.Position())
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return
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}
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// Read the optional 'Else' Nodes.
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if r.Else, ok, err = attributeElseExpression.Parse(pi); err != nil {
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return
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}
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if ok && len(r.Else) == 0 {
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err = parse.Error("attribute if: invalid content or no attributes were found in the else block", pi.Position())
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return
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}
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// Clear any optional whitespace.
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_, _, _ = parse.OptionalWhitespace.Parse(pi)
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// Read the required closing brace.
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if _, ok, err = closeBraceWithOptionalPadding.Parse(pi); err != nil || !ok {
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err = parse.Error("attribute if: missing end (expected '}')", pi.Position())
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return
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}
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return r, true, nil
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}
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var attributeElseExpression parse.Parser[[]Attribute] = attributeElseExpressionParser{}
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type attributeElseExpressionParser struct{}
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func (attributeElseExpressionParser) Parse(in *parse.Input) (r []Attribute, ok bool, err error) {
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start := in.Index()
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// Strip any initial whitespace.
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_, _, _ = parse.OptionalWhitespace.Parse(in)
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// } else {
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var endElseParser = parse.All(
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parse.Rune('}'),
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parse.OptionalWhitespace,
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parse.String("else"),
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parse.OptionalWhitespace,
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parse.Rune('{'))
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if _, ok, err = endElseParser.Parse(in); err != nil || !ok {
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in.Seek(start)
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return
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}
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// Else contents
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if r, ok, err = (attributesParser{}).Parse(in); err != nil || !ok {
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err = parse.Error("attribute if: expected attributes in else block, but none were found", in.Position())
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return
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}
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return r, true, nil
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}
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