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Merge pull request #17 from skyhackvip/feature/7
Feature/7
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,190 @@ | ||
package operator | ||
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||
import ( | ||
"fmt" | ||
"strings" | ||
) | ||
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// evaluate 计算逻辑表达式的值 | ||
func EvaluateBoolExpr(expr string, variables map[string]bool) (bool, error) { | ||
|
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// 将表达式拆分成一个个token | ||
tokens, err := splitExpression(expr) | ||
if err != nil { | ||
return false, err | ||
} | ||
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// 开始执行逻辑运算 | ||
stack := make([]bool, 0) | ||
opStack := make([]string, 0) | ||
for _, token := range tokens { | ||
switch token { | ||
case "&&": | ||
for len(opStack) > 0 && opStack[len(opStack)-1] == "!" { | ||
if len(stack) < 1 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b := stack[len(stack)-1] | ||
stack = stack[:len(stack)-1] | ||
stack = append(stack, !b) | ||
opStack = opStack[:len(opStack)-1] | ||
} | ||
opStack = append(opStack, "&&") | ||
case "||": | ||
for len(opStack) > 0 && (opStack[len(opStack)-1] == "!" || opStack[len(opStack)-1] == "&&") { | ||
if len(stack) < 2 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b1, b2 := stack[len(stack)-2], stack[len(stack)-1] | ||
stack = stack[:len(stack)-2] | ||
op := opStack[len(opStack)-1] | ||
opStack = opStack[:len(opStack)-1] | ||
stack = append(stack, evaluateOp(b1, b2, op)) | ||
} | ||
opStack = append(opStack, "||") | ||
case "!": | ||
opStack = append(opStack, "!") | ||
case "(": | ||
opStack = append(opStack, "(") | ||
case ")": | ||
if len(opStack) < 1 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
for opStack[len(opStack)-1] != "(" { | ||
if len(stack) < 2 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b1, b2 := stack[len(stack)-2], stack[len(stack)-1] | ||
stack = stack[:len(stack)-2] | ||
op := opStack[len(opStack)-1] | ||
opStack = opStack[:len(opStack)-1] | ||
stack = append(stack, evaluateOp(b1, b2, op)) | ||
if len(opStack) == 0 { | ||
return false, fmt.Errorf("unmatched parentheses") | ||
} | ||
} | ||
opStack = opStack[:len(opStack)-1] | ||
if len(opStack) > 0 && opStack[len(opStack)-1] == "!" { | ||
if len(stack) < 1 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b := stack[len(stack)-1] | ||
stack = stack[:len(stack)-1] | ||
stack = append(stack, !b) | ||
opStack = opStack[:len(opStack)-1] | ||
} | ||
default: | ||
if v, ok := variables[token]; ok { | ||
stack = append(stack, v) | ||
if len(opStack) > 0 && opStack[len(opStack)-1] == "!" { | ||
if len(stack) < 1 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b := stack[len(stack)-1] | ||
stack = stack[:len(stack)-1] | ||
stack = append(stack, !b) | ||
opStack = opStack[:len(opStack)-1] | ||
} | ||
} else { | ||
return false, fmt.Errorf("unknown variable %s", token) | ||
} | ||
} | ||
} | ||
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for len(opStack) > 0 { | ||
if len(stack) < 2 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
b1, b2 := stack[len(stack)-2], stack[len(stack)-1] | ||
stack = stack[:len(stack)-2] | ||
op := opStack[len(opStack)-1] | ||
opStack = opStack[:len(opStack)-1] | ||
stack = append(stack, evaluateOp(b1, b2, op)) | ||
} | ||
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if len(stack) != 1 { | ||
return false, fmt.Errorf("invalid expression") | ||
} | ||
return stack[0], nil | ||
} | ||
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// evaluateOp 对两个 bool 值进行逻辑运算 | ||
func evaluateOp(b1, b2 bool, op string) bool { | ||
switch op { | ||
case "&&": | ||
return b1 && b2 | ||
case "||": | ||
return b1 || b2 | ||
default: | ||
panic("unsupported operator: " + op) | ||
} | ||
} | ||
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// isValid 检查表达式是否合法 | ||
func isValid(expr string) bool { | ||
if len(expr) == 0 { | ||
return false | ||
} | ||
allowed := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!()+-_*%/|&," | ||
stack := make([]rune, 0) | ||
for _, ch := range expr { | ||
if ch == '(' { | ||
stack = append(stack, ch) | ||
} else if ch == ')' { | ||
if len(stack) == 0 { | ||
return false | ||
} | ||
stack = stack[:len(stack)-1] | ||
} else if !strings.ContainsRune(allowed, ch) { | ||
return false | ||
} | ||
} | ||
return len(stack) == 0 | ||
} | ||
|
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// splitExpression 将表达式拆分为token | ||
func splitExpression(expr string) ([]string, error) { | ||
expr = strings.ReplaceAll(expr, " ", "") // 去除空格 | ||
if !isValid(expr) { | ||
return nil, fmt.Errorf("invalid expression") | ||
} | ||
tokens := make([]string, 0) | ||
buf := make([]rune, 0) | ||
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for i := 0; i < len(expr); i++ { | ||
ch := rune(expr[i]) | ||
if ch == '&' && i < len(expr)-1 && rune(expr[i+1]) == '&' { | ||
if len(buf) > 0 { | ||
tokens = append(tokens, string(buf)) | ||
buf = []rune{} | ||
} | ||
tokens = append(tokens, "&&") | ||
i++ | ||
} else if ch == '|' && i < len(expr)-1 && rune(expr[i+1]) == '|' { | ||
if len(buf) > 0 { | ||
tokens = append(tokens, string(buf)) | ||
buf = []rune{} | ||
} | ||
tokens = append(tokens, "||") | ||
i++ | ||
} else if ch == '!' || ch == '(' || ch == ')' { | ||
if len(buf) > 0 { | ||
tokens = append(tokens, string(buf)) | ||
buf = []rune{} | ||
} | ||
tokens = append(tokens, string(ch)) | ||
} else if ch == ',' { | ||
if len(buf) > 0 { | ||
tokens = append(tokens, string(buf)) | ||
buf = []rune{} | ||
} | ||
tokens = append(tokens, string(ch)) | ||
} else { | ||
buf = append(buf, ch) | ||
} | ||
} | ||
if len(buf) > 0 { | ||
tokens = append(tokens, string(buf)) | ||
} | ||
return tokens, nil | ||
} |
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