/
switchexpressionparser.go
102 lines (82 loc) · 2.62 KB
/
switchexpressionparser.go
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package parser
import (
"github.com/a-h/parse"
"github.com/a-h/templ/parser/v2/goexpression"
)
var switchExpression parse.Parser[Node] = switchExpressionParser{}
type switchExpressionParser struct{}
func (_ switchExpressionParser) Parse(pi *parse.Input) (n Node, ok bool, err error) {
var r SwitchExpression
start := pi.Index()
// Check the prefix first.
if !peekPrefix(pi, "switch ") {
pi.Seek(start)
return
}
// Parse the Go switch expresion.
if r.Expression, err = parseGo("switch", pi, goexpression.Switch); err != nil {
return r, false, err
}
// Eat " {\n".
if _, ok, err = parse.All(openBraceWithOptionalPadding, parse.NewLine).Parse(pi); err != nil || !ok {
err = parse.Error("switch: "+unterminatedMissingCurly, pi.PositionAt(start))
return
}
// Once we've had the start of a switch block, we must conclude the block.
// Read the optional 'case' nodes.
for {
var ce CaseExpression
ce, ok, err = caseExpressionParser.Parse(pi)
if err != nil {
return
}
if !ok {
break
}
r.Cases = append(r.Cases, ce)
}
// Read the required closing brace.
if _, ok, err = closeBraceWithOptionalPadding.Parse(pi); err != nil || !ok {
err = parse.Error("switch: "+unterminatedMissingEnd, pi.Position())
return
}
return r, true, nil
}
var caseExpressionStartParser = parse.Func(func(pi *parse.Input) (r Expression, ok bool, err error) {
start := pi.Index()
// Optional whitespace.
if _, _, err = parse.OptionalWhitespace.Parse(pi); err != nil {
return
}
// Strip leading whitespace and look for `case ` or `default`.
if !peekPrefix(pi, "case ", "default") {
pi.Seek(start)
return r, false, nil
}
// Parse the Go expresion.
if r, err = parseGo("case", pi, goexpression.Case); err != nil {
return r, false, err
}
// Eat terminating newline.
_, _, _ = parse.ZeroOrMore(parse.String(" ")).Parse(pi)
_, _, _ = parse.NewLine.Parse(pi)
return r, true, nil
})
var caseExpressionParser = parse.Func(func(pi *parse.Input) (r CaseExpression, ok bool, err error) {
if r.Expression, ok, err = caseExpressionStartParser.Parse(pi); err != nil || !ok {
return
}
// Read until the next case statement, default, or end of the block.
pr := newTemplateNodeParser(parse.Any(StripType(closeBraceWithOptionalPadding), StripType(caseExpressionStartParser)), "closing brace or case expression")
var nodes Nodes
if nodes, ok, err = pr.Parse(pi); err != nil || !ok {
err = parse.Error("case: expected nodes, but none were found", pi.Position())
return
}
r.Children = nodes.Nodes
// Optional whitespace.
if _, ok, err = parse.OptionalWhitespace.Parse(pi); err != nil || !ok {
return
}
return r, true, nil
})