150 lines
3.9 KiB
Go
150 lines
3.9 KiB
Go
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package parser
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import (
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"fmt"
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"github.com/a-h/parse"
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)
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// TemplateExpression.
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// TemplateExpression.
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// templ Func(p Parameter) {
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// templ (data Data) Func(p Parameter) {
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// templ (data []string) Func(p Parameter) {
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type templateExpression struct {
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Expression Expression
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}
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var templateExpressionParser = parse.Func(func(pi *parse.Input) (r templateExpression, ok bool, err error) {
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start := pi.Index()
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if !peekPrefix(pi, "templ ") {
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return r, false, nil
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}
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// Once we have the prefix, everything to the brace is Go.
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// e.g.
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// templ (x []string) Test() {
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// becomes:
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// func (x []string) Test() templ.Component {
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if _, r.Expression, err = parseTemplFuncDecl(pi); err != nil {
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return r, false, err
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}
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// Eat " {\n".
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if _, ok, err = parse.All(openBraceWithOptionalPadding, parse.StringFrom(parse.Optional(parse.NewLine))).Parse(pi); err != nil || !ok {
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err = parse.Error("templ: malformed templ expression, expected `templ functionName() {`", pi.PositionAt(start))
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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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const (
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unterminatedMissingCurly = `unterminated (missing closing '{\n') - https://templ.guide/syntax-and-usage/statements#incomplete-statements`
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unterminatedMissingEnd = `missing end (expected '}') - https://templ.guide/syntax-and-usage/statements#incomplete-statements`
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)
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// Template node (element, call, if, switch, for, whitespace etc.)
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func newTemplateNodeParser[TUntil any](until parse.Parser[TUntil], untilName string) templateNodeParser[TUntil] {
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return templateNodeParser[TUntil]{
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until: until,
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untilName: untilName,
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}
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}
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type templateNodeParser[TUntil any] struct {
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until parse.Parser[TUntil]
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untilName string
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}
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var rawElements = parse.Any(styleElement, scriptElement)
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var templateNodeSkipParsers = []parse.Parser[Node]{
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voidElementCloser, // </br>, </img> etc. - should be ignored.
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}
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var templateNodeParsers = []parse.Parser[Node]{
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docType, // <!DOCTYPE html>
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htmlComment, // <!--
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goComment, // // or /*
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rawElements, // <text>, <>, or <style> element (special behaviour - contents are not parsed).
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element, // <a>, <br/> etc.
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ifExpression, // if {}
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forExpression, // for {}
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switchExpression, // switch {}
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callTemplateExpression, // {! TemplateName(a, b, c) }
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templElementExpression, // @TemplateName(a, b, c) { <div>Children</div> }
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childrenExpression, // { children... }
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goCode, // {{ myval := x.myval }}
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stringExpression, // { "abc" }
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whitespaceExpression, // { " " }
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textParser, // anything & everything accepted...
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}
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func (p templateNodeParser[T]) Parse(pi *parse.Input) (op Nodes, ok bool, err error) {
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outer:
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for {
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// Check if we've reached the end.
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if p.until != nil {
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start := pi.Index()
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_, ok, err = p.until.Parse(pi)
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if err != nil {
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return
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}
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if ok {
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pi.Seek(start)
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return op, true, nil
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}
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}
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// Skip any nodes that we don't care about.
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for _, p := range templateNodeSkipParsers {
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_, matched, err := p.Parse(pi)
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if err != nil {
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return Nodes{}, false, err
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}
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if matched {
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continue outer
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}
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}
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// Attempt to parse a node.
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// Loop through the parsers and try to parse a node.
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var matched bool
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for _, p := range templateNodeParsers {
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var node Node
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node, matched, err = p.Parse(pi)
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if err != nil {
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return Nodes{}, false, err
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}
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if matched {
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op.Nodes = append(op.Nodes, node)
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break
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}
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}
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if matched {
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continue
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}
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if p.until == nil {
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// In this case, we're just reading as many nodes as we can until we can't read any more.
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// If we've reached here, we couldn't find a node.
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// The element parser checks the final node returned to make sure it's the expected close tag.
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break
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}
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err = UntilNotFoundError{
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ParseError: parse.Error(fmt.Sprintf("%v not found", p.untilName), pi.Position()),
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}
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return
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}
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return op, true, nil
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}
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type UntilNotFoundError struct {
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parse.ParseError
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}
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