forked from cockroachdb/cockroach
/
parse.go
89 lines (77 loc) · 2.33 KB
/
parse.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
// Copyright 2015 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. See the AUTHORS file
// for names of contributors.
//
// Author: Peter Mattis (peter@cockroachlabs.com)
// This code was derived from https://github.com/youtube/vitess.
//
// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file
package parser
import (
"bytes"
"errors"
"github.com/cockroachdb/cockroach/util"
)
//go:generate make
// StatementList is a list of statements.
type StatementList []Statement
func (l StatementList) String() string {
var buf bytes.Buffer
for i, s := range l {
if i > 0 {
buf.WriteString("; ")
}
buf.WriteString(s.String())
}
return buf.String()
}
// Syntax is an enum of the various syntax types.
type Syntax int
//go:generate stringer -type=Syntax
const (
Traditional Syntax = iota
Modern
)
// Parse parses the sql and returns a list of statements.
func Parse(sql string, syntax Syntax) (StatementList, error) {
s := newScanner(sql, syntax)
if sqlParse(s) != 0 {
return nil, errors.New(s.lastError)
}
return s.stmts, nil
}
// ParseTraditional is short-hand for Parse(sql, Traditional)
func ParseTraditional(sql string) (StatementList, error) {
return Parse(sql, Traditional)
}
// ParseExpr parses a sql expression.
func ParseExpr(expr string, syntax Syntax) (Expr, error) {
stmts, err := Parse(`SELECT `+expr, syntax)
if err != nil {
return nil, err
}
if len(stmts) != 1 {
return nil, util.Errorf("expected 1 statement, but found %d", len(stmts))
}
sel, ok := stmts[0].(*Select)
if !ok {
return nil, util.Errorf("expected a SELECT statement, but found %T", stmts[0])
}
if n := len(sel.Exprs); n != 1 {
return nil, util.Errorf("expected 1 expression, but found %d", n)
}
return sel.Exprs[0].Expr, nil
}