使用 Go 实现的数学表达式解析计算引擎库,无任何依赖,相对比较完整的完成了数学表达式解析执行,包括词法分析、语法分析、构建AST、运行。
能够处理的表达式样例:
1+127-21+(3-4)*6/2.5
(88+(1+8)*6)/2+99
123_345_456 * 1.5 - 2 ^ 4
-4 * 6 + 2e2 - 1.6e-3
sin(pi/2)+cos(45-45*1)+tan(pi/4)
99+abs(-1)-ceil(88.8)+floor(88.8)
max(min(2^3, 3^2), 10*1.5-7)
你可以直接引用该库嵌入到自己的程序中:
go get -u github.com/dengsgo/math-engine
在代码中引入:
import "github.com/dengsgo/math-engine/engine"
e.g. 1 直接调用解析执行函数 :
import "github.com/dengsgo/math-engine/engine" func main() { s := "1 + 2 * 6 / 4 + (456 - 8 * 9.2) - (2 + 4 ^ 5)" // call top level function r, err := engine.ParseAndExec(s) if err != nil { fmt.Println(err) } fmt.Printf("%s = %v", s, r) }
e.g. 2 依次调用函数,手动执行 :
import "github.com/dengsgo/math-engine/engine" func main() { s := "1 + 2 * 6 / 4 + (456 - 8 * 9.2) - (2 + 4 ^ 5)" exec(s) } // call engine // one by one func exec(exp string) { // input text -> []token toks, err := engine.Parse(exp) if err != nil { fmt.Println("ERROR: " + err.Error()) return } // []token -> AST Tree ast := engine.NewAST(toks, exp) if ast.Err != nil { fmt.Println("ERROR: " + ast.Err.Error()) return } // AST builder ar := ast.ParseExpression() if ast.Err != nil { fmt.Println("ERROR: " + ast.Err.Error()) return } fmt.Printf("ExprAST: %+v\n", ar) // AST traversal -> result r := engine.ExprASTResult(ar) fmt.Println("progressing ...\t", r) fmt.Printf("%s = %v\n", exp, r) }
编译运行,应该可以看到如下输出:
ExprAST: {Op:- Lhs:{Op:+ Lhs:{Op:+ Lhs:{Val:1} Rhs:{Op:/ Lhs:{Op:* Lhs:{Val:2} Rhs:{Val:6}} Rhs:{Val:4}}} Rhs:{Op:- Lhs:{Val:456} Rhs:{Op:* Lhs:{Val:8} Rhs:{Val:9.2}}}} Rhs:{Op:+ Lhs:{Val:2} Rhs:{Op:^ Lhs:{Val:4} Rhs:{Val:5}}}} progressing ... -639.6 1+2*6/4+(456-8*9.2)-(2+4^5) = -639.6
三角函数的参数类型默认为弧度RadianMode,e.g. sin(pi/2) = 1.
RadianMode
sin(pi/2) = 1
你可以通过设置 TrigonometricMode 调整参数类型,可选 弧度RadianMode、角度AngleMode,e.g. :
TrigonometricMode
AngleMode
import "github.com/dengsgo/math-engine/engine" func main() { s := "1 + sin(90)" engine.TrigonometricMode = engine.AngleMode engine.ParseAndExec(s) // will return 2, nil s = "1 + sin(pi/2)" engine.TrigonometricMode = engine.RadianMode engine.ParseAndExec(s) // will return 2, nil }
godoc.org/github.com/dengsgo/math- engine/engine
go version 1.12
# Compile Demo go test go build ./math-engine
也可以直接下载已编译好的二进制文件,直接运行:
Github Releases
请阅读我的博客文章:用 Go 实现一个完整的数学表达式计算引擎
+
-
*
/
%
^
1.2e7
1.2e-7
()
1+2*6/4+(456-8*9.2)-(2+4^5)*2e3+1.2e-2
123_456_789
sin, cos, tan, cot, sec, csc
abs, ceil, floor, sqrt, cbrt
友好的错误消息 e.g.
input /> 123+89-0.0.9 ERROR: strconv.ParseFloat: parsing “0.0.9”: invalid syntax want ‘(‘ or ‘0-9’ but get ‘0.0.9’
123+89-0.0.9 ^