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|
package participle
import (
"bytes"
"fmt"
"strings"
"github.com/alecthomas/participle/lexer"
)
type stringerVisitor struct {
bytes.Buffer
seen map[node]bool
}
func stringern(n node, depth int) string {
v := &stringerVisitor{seen: map[node]bool{}}
v.visit(n, depth)
return v.String()
}
func stringer(n node) string {
return stringern(n, 1)
}
func (s *stringerVisitor) visit(n node, depth int) { // nolint: gocognit
if s.seen[n] || depth <= 0 {
fmt.Fprintf(s, "...")
return
}
s.seen[n] = true
switch n := n.(type) {
case *disjunction:
for i, c := range n.nodes {
if i > 0 {
fmt.Fprint(s, " | ")
}
s.visit(c, depth)
}
case *strct:
s.visit(n.expr, depth)
case *sequence:
c := n
for i := 0; c != nil && depth-i > 0; c, i = c.next, i+1 {
if c != n {
fmt.Fprint(s, " ")
}
s.visit(c.node, depth-i)
}
case *parseable:
fmt.Fprintf(s, "<%s>", strings.ToLower(n.t.Name()))
case *capture:
if _, ok := n.node.(*parseable); ok {
fmt.Fprintf(s, "<%s>", strings.ToLower(n.field.Name))
} else {
if n.node == nil {
fmt.Fprintf(s, "<%s>", strings.ToLower(n.field.Name))
} else {
s.visit(n.node, depth)
}
}
case *reference:
fmt.Fprintf(s, "<%s>", strings.ToLower(n.identifier))
case *optional:
composite := compositeNode(map[node]bool{}, n, true)
if composite {
fmt.Fprint(s, "(")
}
s.visit(n.node, depth)
if composite {
fmt.Fprint(s, ")")
}
fmt.Fprint(s, "?")
case *repetition:
composite := compositeNode(map[node]bool{}, n, true)
if composite {
fmt.Fprint(s, "(")
}
s.visit(n.node, depth)
if composite {
fmt.Fprint(s, ")")
}
fmt.Fprint(s, "*")
case *negation:
fmt.Fprintf(s, "!")
composite := compositeNode(map[node]bool{}, n, true)
if composite {
fmt.Fprint(s, "(")
}
s.visit(n.node, depth)
if composite {
fmt.Fprint(s, ")")
}
case *literal:
fmt.Fprintf(s, "%q", n.s)
if n.t != lexer.EOF && n.s == "" {
fmt.Fprintf(s, ":%s", n.tt)
}
case *group:
composite := (n.mode != groupMatchOnce) && compositeNode(map[node]bool{}, n, true)
if composite {
fmt.Fprint(s, "(")
}
if child, ok := n.expr.(*group); ok && child.mode == groupMatchOnce {
s.visit(child.expr, depth)
} else if child, ok := n.expr.(*capture); ok {
if grandchild, ok := child.node.(*group); ok && grandchild.mode == groupMatchOnce {
s.visit(grandchild.expr, depth)
} else {
s.visit(n.expr, depth)
}
} else {
s.visit(n.expr, depth)
}
if composite {
fmt.Fprint(s, ")")
}
switch n.mode {
case groupMatchNonEmpty:
fmt.Fprintf(s, "!")
case groupMatchZeroOrOne:
fmt.Fprintf(s, "?")
case groupMatchZeroOrMore:
fmt.Fprintf(s, "*")
case groupMatchOneOrMore:
fmt.Fprintf(s, "+")
}
default:
panic("unsupported")
}
}
func compositeNode(seen map[node]bool, n node, strctAsComposite bool) bool {
if n == nil || seen[n] {
return false
}
seen[n] = true
switch n := n.(type) {
case *sequence:
return n.next != nil
case *disjunction:
for _, c := range n.nodes {
if compositeNode(seen, c, strctAsComposite) {
return true
}
}
return false
case *reference, *literal, *parseable:
return false
case *negation:
return compositeNode(seen, n.node, strctAsComposite)
case *strct:
return strctAsComposite && compositeNode(seen, n.expr, strctAsComposite)
case *capture:
return compositeNode(seen, n.node, strctAsComposite)
case *optional:
return compositeNode(seen, n.node, strctAsComposite)
case *repetition:
return compositeNode(seen, n.node, strctAsComposite)
case *group:
return compositeNode(seen, n.expr, strctAsComposite)
default:
panic("unsupported")
}
}
|
