forked from cockroachdb/cockroach
/
render.go
98 lines (94 loc) · 2.66 KB
/
render.go
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// Copyright 2017 The Cockroach Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
package ir
import (
"bytes"
"fmt"
)
// ToString converts a syntax tree back to the input syntax,
// using Format()
func ToString(ast interface{}) string {
var buf bytes.Buffer
Format(&buf, 0, ast)
return buf.String()
}
// Format converts a syntax tree back to the input syntax.
func Format(buf *bytes.Buffer, ident int, ast interface{}) {
switch n := ast.(type) {
case *NamedType:
if n.Type == nil {
fmt.Fprintf(buf, "(typedef :name %s)", n.Name)
} else {
fmt.Fprintf(buf, "(typedef\n%*s:name %s", ident+4, "", n.Name)
if n.Type != nil {
fmt.Fprintf(buf, "\n%*s:type", ident+4, "")
Format(buf, ident+8, n.Type)
}
buf.WriteByte(')')
}
case *EnumItem:
fmt.Fprintf(buf, "(const :name %s :tag %d)", n.Name, n.Tag)
case *EnumType:
if len(n.Items) == 0 {
buf.WriteString(" (enum)")
} else {
fmt.Fprintf(buf, "\n%*s(enum\n", ident, "")
for i := range n.Items {
fmt.Fprintf(buf, "%*s", ident+4, "")
Format(buf, ident+8, &n.Items[i])
buf.WriteByte('\n')
}
fmt.Fprintf(buf, "%*s)", ident, "")
}
case *StructItem:
fmt.Fprintf(buf, "(field :name %s :type %s :isslice %t :tag %d)",
n.Name, n.Type.Name, n.IsSlice, n.Tag)
case *StructType:
if len(n.Items) == 0 {
buf.WriteString(" (struct)")
} else {
fmt.Fprintf(buf, "\n%*s(struct\n", ident, "")
for i := range n.Items {
fmt.Fprintf(buf, "%*s", ident+4, "")
Format(buf, ident+8, &n.Items[i])
buf.WriteByte('\n')
}
fmt.Fprintf(buf, "%*s)", ident, "")
}
case *SumItem:
fmt.Fprintf(buf, "(alt :type %s :tag %d)", n.Type.Name, n.Tag)
case *SumType:
if len(n.Items) == 0 {
buf.WriteString("(sum)")
} else {
fmt.Fprintf(buf, "\n%*s(sum\n", ident, "")
for i := range n.Items {
fmt.Fprintf(buf, "%*s", ident+4, "")
Format(buf, ident+8, &n.Items[i])
buf.WriteByte('\n')
}
fmt.Fprintf(buf, "%*s)", ident, "")
}
case []NamedType:
for i := range n {
if i > 0 {
fmt.Fprintf(buf, "%*s", ident, "")
}
Format(buf, ident, &n[i])
buf.WriteByte('\n')
}
default:
panic(fmt.Sprintf("unhandled type: %T - %+v", ast, ast))
}
}