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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
// nolint: govet
package main
import (
"github.com/alecthomas/kong"
"github.com/alecthomas/repr"
"github.com/alecthomas/participle/v2"
"github.com/alecthomas/participle/v2/lexer"
)
type Boolean bool
func (b *Boolean) Capture(values []string) error {
*b = values[0] == "TRUE"
return nil
}
// Select based on http://www.h2database.com/html/grammar.html
type Select struct {
Top *Term `"SELECT" ( "TOP" @@ )?`
Distinct bool `( @"DISTINCT"`
All bool ` | @"ALL" )?`
Expression *SelectExpression `@@`
From *From `"FROM" @@`
Limit *Expression `( "LIMIT" @@ )?`
Offset *Expression `( "OFFSET" @@ )?`
GroupBy *Expression `( "GROUP" "BY" @@ )?`
}
type From struct {
TableExpressions []*TableExpression `@@ ( "," @@ )*`
Where *Expression `( "WHERE" @@ )?`
}
type TableExpression struct {
Table string `( @Ident ( "." @Ident )*`
Select *Select ` | "(" @@ ")"`
Values []*Expression ` | "VALUES" "(" @@ ( "," @@ )* ")")`
As string `( "AS" @Ident )?`
}
type SelectExpression struct {
All bool ` @"*"`
Expressions []*AliasedExpression `| @@ ( "," @@ )*`
}
type AliasedExpression struct {
Expression *Expression `@@`
As string `( "AS" @Ident )?`
}
type Expression struct {
Or []*OrCondition `@@ ( "OR" @@ )*`
}
type OrCondition struct {
And []*Condition `@@ ( "AND" @@ )*`
}
type Condition struct {
Operand *ConditionOperand ` @@`
Not *Condition `| "NOT" @@`
Exists *Select `| "EXISTS" "(" @@ ")"`
}
type ConditionOperand struct {
Operand *Operand `@@`
ConditionRHS *ConditionRHS `@@?`
}
type ConditionRHS struct {
Compare *Compare ` @@`
Is *Is `| "IS" @@`
Between *Between `| "BETWEEN" @@`
In *In `| "IN" "(" @@ ")"`
Like *Like `| "LIKE" @@`
}
type Compare struct {
Operator string `@( "<>" | "<=" | ">=" | "=" | "<" | ">" | "!=" )`
Operand *Operand `( @@`
Select *CompareSelect ` | @@ )`
}
type CompareSelect struct {
All bool `( @"ALL"`
Any bool ` | @"ANY"`
Some bool ` | @"SOME" )`
Select *Select `"(" @@ ")"`
}
type Like struct {
Not bool `[ @"NOT" ]`
Operand *Operand `@@`
}
type Is struct {
Not bool `[ @"NOT" ]`
Null bool `( @"NULL"`
DistinctFrom *Operand ` | "DISTINCT" "FROM" @@ )`
}
type Between struct {
Start *Operand `@@`
End *Operand `"AND" @@`
}
type In struct {
Select *Select ` @@`
Expressions []*Expression `| @@ ( "," @@ )*`
}
type Operand struct {
Summand []*Summand `@@ ( "|" "|" @@ )*`
}
type Summand struct {
LHS *Factor `@@`
Op string `[ @("+" | "-")`
RHS *Factor ` @@ ]`
}
type Factor struct {
LHS *Term `@@`
Op string `( @("*" | "/" | "%")`
RHS *Term ` @@ )?`
}
type Term struct {
Select *Select ` @@`
Value *Value `| @@`
SymbolRef *SymbolRef `| @@`
SubExpression *Expression `| "(" @@ ")"`
}
type SymbolRef struct {
Symbol string `@Ident @( "." Ident )*`
Parameters []*Expression `( "(" @@ ( "," @@ )* ")" )?`
}
type Value struct {
Wildcard bool `( @"*"`
Number *float64 ` | @Number`
String *string ` | @String`
Boolean *Boolean ` | @("TRUE" | "FALSE")`
Null bool ` | @"NULL"`
Array *Array ` | @@ )`
}
type Array struct {
Expressions []*Expression `"(" @@ ( "," @@ )* ")"`
}
var (
cli struct {
SQL string `arg:"" required:"" help:"SQL to parse."`
}
sqlLexer = lexer.MustSimple([]lexer.SimpleRule{
{`Keyword`, `(?i)\b(SELECT|FROM|TOP|DISTINCT|ALL|WHERE|GROUP|BY|HAVING|UNION|MINUS|EXCEPT|INTERSECT|ORDER|LIMIT|OFFSET|TRUE|FALSE|NULL|IS|NOT|ANY|SOME|BETWEEN|AND|OR|LIKE|AS|IN)\b`},
{`Ident`, `[a-zA-Z_][a-zA-Z0-9_]*`},
{`Number`, `[-+]?\d*\.?\d+([eE][-+]?\d+)?`},
{`String`, `'[^']*'|"[^"]*"`},
{`Operators`, `<>|!=|<=|>=|[-+*/%,.()=<>]`},
{"whitespace", `\s+`},
})
parser = participle.MustBuild[Select](
participle.Lexer(sqlLexer),
participle.Unquote("String"),
participle.CaseInsensitive("Keyword"),
// participle.Elide("Comment"),
// Need to solve left recursion detection first, if possible.
// participle.UseLookahead(),
)
)
func main() {
ctx := kong.Parse(&cli)
sql, err := parser.ParseString("", cli.SQL)
repr.Println(sql, repr.Indent(" "), repr.OmitEmpty(true))
ctx.FatalIfErrorf(err)
}
|
