ast

Documentation

Index

• Constants
• func ErrPos(s string, pos int) string
• func ExprASTResult(expr ExprAST, exprDatas ...ParameterExprData) float64
• func ExprASTResultByAntlr(expr ExprAST, exprDatas ParameterExprData) float64
• func ExprASTResultByAntlrWithStatement(expr ExprAST, exprDatas ParameterExprData) float64
• func ExprASTResultWithType(expr ExprAST, exprDatas ParameterExprData, astType string) float64
• type AST
  • func NewAST(toks []*Token, s string) *AST
  • func (a *AST) ParseExpression() ExprAST
• type BinaryExprAST
• type ExprAST
  • func GetExpAST(source string) (ExprAST, error)
  • func GetExpASTByAntlr(source string) (ExprAST, error)
  • func GetExpASTByAntlrWithStatement(source, returnParam string) (ExprAST, error)
  • func GetExpASTWithType(source, astType string) (ExprAST, error)
• type NumberExprAST
• type ParameterExprAST
• type ParameterExprData
• type Parser
• type Token
  • func Parse(s string) ([]*Token, error)

Constants

const (
	// 字面量，e.g. 50
	Literal = iota
	// 操作符, e.g. + - * /
	Operator

	// 参数变量
	Parameter
)

Functions

func ErrPos

func ErrPos(s string, pos int) string

对错误包装，进行可视化展示

func ExprASTResult

func ExprASTResult(expr ExprAST, exprDatas ...ParameterExprData) float64

一个典型的后序遍历求解算法

func ExprASTResultByAntlr

func ExprASTResultByAntlr(expr ExprAST, exprDatas ParameterExprData) float64

func ExprASTResultByAntlrWithStatement

func ExprASTResultByAntlrWithStatement(expr ExprAST, exprDatas ParameterExprData) float64

func ExprASTResultWithType

func ExprASTResultWithType(expr ExprAST, exprDatas ParameterExprData, astType string) float64

Types

type AST

type AST struct {
	// 词法分析的结果
	Tokens []*Token

	// 错误收集
	Err error
	// contains filtered or unexported fields
}

AST 生成器结构体

func NewAST

func NewAST(toks []*Token, s string) *AST

生成一个 AST 结构指针

func (*AST) ParseExpression

func (a *AST) ParseExpression() ExprAST

语法分析器入口

type BinaryExprAST

type BinaryExprAST struct {
	// 操作符
	Op string
	// 左右节点，可能是 数字表达式节点/操作表达式节点/nil
	Lhs,
	Rhs ExprAST
}

操作表达式节点

type ExprAST

type ExprAST interface {
	// contains filtered or unexported methods
}

基础表达式节点接口

func GetExpAST

func GetExpAST(source string) (ExprAST, error)

func GetExpASTByAntlr

func GetExpASTByAntlr(source string) (ExprAST, error)

func GetExpASTByAntlrWithStatement

func GetExpASTByAntlrWithStatement(source, returnParam string) (ExprAST, error)

func GetExpASTWithType

func GetExpASTWithType(source, astType string) (ExprAST, error)

type NumberExprAST

type NumberExprAST struct {
	// 具体的值
	Val float64
}

数字表达式节点

type ParameterExprAST

type ParameterExprAST struct {
	Val string
}

type ParameterExprData

type ParameterExprData interface {
	FloatExprData(string) (float64, error)
	ExprData() map[string]interface{}
}

type Parser

type Parser struct {
	// 输入的字符串
	Source string
	// contains filtered or unexported fields
}

定义一个结构体，描述一个词法分析器

type Token

type Token struct {
	// 原始字符
	Tok string
	// 类型，有 Literal、Operator 两种
	Type int

	Offset int
}

func Parse

func Parse(s string) ([]*Token, error)

封装词法分析过程，直接调用该函数即可解析字符串为[]Token