57 lines
1.2 KiB
Go
57 lines
1.2 KiB
Go
package participle
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import (
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"fmt"
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"io"
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"reflect"
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"strings"
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)
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// Trace the parse to "w".
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func Trace(w io.Writer) Option {
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return func(p *Parser) error {
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p.trace = w
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return nil
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}
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}
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type trace struct {
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w io.Writer
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indent int
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node
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}
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func (t *trace) Parse(ctx *parseContext, parent reflect.Value) ([]reflect.Value, error) {
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tok, _ := ctx.Peek(0)
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fmt.Fprintf(t.w, "%s%q %s\n", strings.Repeat(" ", t.indent), tok, t.node.GoString())
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return t.node.Parse(ctx, parent)
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}
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func injectTrace(w io.Writer, indent int, n node) node {
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out := &trace{w, indent, n}
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switch n := n.(type) {
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case *disjunction:
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for i, child := range n.nodes {
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n.nodes[i] = injectTrace(w, indent+2, child)
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}
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case *strct:
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n.expr = injectTrace(w, indent+2, n.expr)
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case *sequence:
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n.node = injectTrace(w, indent+2, n.node)
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// injectTrace(w, indent, n.next)
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case *parseable:
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case *capture:
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n.node = injectTrace(w, indent+2, n.node)
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case *reference:
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case *optional:
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n.node = injectTrace(w, indent+2, n.node)
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case *repetition:
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n.node = injectTrace(w, indent+2, n.node)
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case *negation:
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n.node = injectTrace(w, indent+2, n.node)
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case *literal:
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case *group:
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n.expr = injectTrace(w, indent+2, n.expr)
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}
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return out
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}
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