what
how:
- 词汇分析: token list
- 语法分析: ast
- generate code
ast tree
what: token之间的关系， 用树形式表示出来
parse tree vs abstract tree: ast 是 parse tree 进一步提炼
go parse work
how:
- goToken: getTokenList
- parser: getAst
rules
the proces:
- rules and datasources
- parse
parse: bool 表达式
- logic ops: ||, &&
- compare: >=, <=, !=
list:
- https://github.com/Knetic/govaluate
example:
a > 1 && (b <10 || a < 199)
binaryExp
- x: binaryExp
- x:ident, a
- y: literal . 1
- op， >
- y: parentExp
- x:binExp
- x:binaryExp
- x: ident, b
- y:literal, 10
- op, <
- y:binaryExp
- op: ||
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0 *ast.BinaryExpr {
1 . X: *ast.BinaryExpr {
2 . . X: *ast.Ident {
3 . . . NamePos: -
4 . . . Name: "a"
5 . . }
6 . . OpPos: -
7 . . Op: >
8 . . Y: *ast.BasicLit {
9 . . . ValuePos: -
10 . . . Kind: INT
11 . . . Value: "1"
12 . . }
13 . }
14 . OpPos: -
15 . Op: &&
16 . Y: *ast.ParenExpr {
17 . . Lparen: -
18 . . X: *ast.BinaryExpr {
19 . . . X: *ast.BinaryExpr {
20 . . . . X: *ast.Ident {
21 . . . . . NamePos: -
22 . . . . . Name: "b"
23 . . . . }
24 . . . . OpPos: -
25 . . . . Op: <
26 . . . . Y: *ast.BasicLit {
27 . . . . . ValuePos: -
28 . . . . . Kind: INT
29 . . . . . Value: "10"
30 . . . . }
31 . . . }
32 . . . OpPos: -
33 . . . Op: ||
34 . . . Y: *ast.BinaryExpr {
35 . . . . X: *ast.Ident {
36 . . . . . NamePos: -
37 . . . . . Name: "a"
38 . . . . }
39 . . . . OpPos: -
40 . . . . Op: <
41 . . . . Y: *ast.BasicLit {
42 . . . . . ValuePos: -
43 . . . . . Kind: INT
44 . . . . . Value: "199"
45 . . . . }
46 . . . }
47 . . }
48 . . Rparen: -
49 . }
50 }
|
