mirror of
https://github.com/danog/liquid.git
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118 lines
3.4 KiB
Go
118 lines
3.4 KiB
Go
package render
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import (
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"io"
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"sort"
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"github.com/osteele/liquid/parser"
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)
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// BlockCompiler builds a renderer for the tag instance.
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type BlockCompiler func(BlockNode) (func(io.Writer, Context) error, error)
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// blockSyntax tells the parser how to parse a control tag.
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type blockSyntax struct {
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name string
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isClauseTag, isEndTag bool
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startName string // for an end tag, the name of the correspondign start tag
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parents map[string]bool // if non-nil, must be an immediate clause of one of these
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parser BlockCompiler
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}
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func (s *blockSyntax) CanHaveParent(parent parser.BlockSyntax) bool {
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switch {
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case s.isClauseTag:
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return parent != nil && s.parents[parent.TagName()]
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case s.isEndTag:
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return parent != nil && parent.TagName() == s.startName
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default:
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return true
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}
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}
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func (s *blockSyntax) IsBlock() bool { return true }
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func (s *blockSyntax) IsBlockEnd() bool { return s.isEndTag }
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func (s *blockSyntax) IsBlockStart() bool { return !s.isClauseTag && !s.isEndTag }
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func (s *blockSyntax) IsClause() bool { return s.isClauseTag }
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func (s *blockSyntax) RequiresParent() bool { return s.isClauseTag || s.isEndTag }
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func (s *blockSyntax) ParentTags() (parents []string) {
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for k := range s.parents {
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parents = append(parents, k)
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}
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sort.Strings(parents)
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return
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}
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func (s *blockSyntax) TagName() string { return s.name }
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func (g grammar) addBlockDef(ct *blockSyntax) {
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if g.blockDefs[ct.name] != nil {
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panic("duplicate definition of " + ct.name)
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}
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g.blockDefs[ct.name] = ct
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}
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func (g grammar) findBlockDef(name string) (*blockSyntax, bool) {
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ct, found := g.blockDefs[name]
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return ct, found
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}
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// BlockSyntax is part of the Grammar interface.
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func (g grammar) BlockSyntax(name string) (parser.BlockSyntax, bool) {
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ct, found := g.blockDefs[name]
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return ct, found
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}
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type blockDefBuilder struct {
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grammar
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tag *blockSyntax
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}
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// AddBlock defines a control tag and its matching end tag.
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func (g grammar) AddBlock(name string) blockDefBuilder { // nolint: golint
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ct := &blockSyntax{name: name}
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g.addBlockDef(ct)
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g.addBlockDef(&blockSyntax{name: "end" + name, isEndTag: true, startName: name})
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return blockDefBuilder{g, ct}
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}
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// Clause tells the parser that the named tag can appear immediately between this tag and its end tag,
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// so long as it is not nested within any other control tag.
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func (b blockDefBuilder) Clause(name string) blockDefBuilder {
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if b.blockDefs[name] == nil {
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b.addBlockDef(&blockSyntax{name: name, isClauseTag: true})
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}
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c := b.blockDefs[name]
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if !c.isClauseTag {
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panic(name + " has already been defined as a non-clause")
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}
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if len(c.parents) == 0 {
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c.parents = make(map[string]bool)
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}
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c.parents[b.tag.name] = true
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return b
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}
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// SameSyntaxAs tells the parser that this tag has the same syntax as the named tag.
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// func (b blockDefBuilder) SameSyntaxAs(name string) blockDefBuilder {
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// rt := b.blockDefs[name]
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// if rt == nil {
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// panic(fmt.Errorf("undefined: %s", name))
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// }
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// b.tag.syntaxModel = rt
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// return b
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// }
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// Compiler sets the parser for a control tag definition.
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func (b blockDefBuilder) Compiler(fn BlockCompiler) {
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b.tag.parser = fn
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}
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// Renderer sets the render action for a control tag definition.
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func (b blockDefBuilder) Renderer(fn func(io.Writer, Context) error) {
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b.tag.parser = func(node BlockNode) (func(io.Writer, Context) error, error) {
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// TODO syntax error if there are arguments?
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return fn, nil
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}
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}
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