├── .gitignore ├── Calc.g4 ├── LICENSE ├── Makefile ├── README.md ├── go.mod ├── go.sum ├── listen └── main.go └── visitor └── main.go /.gitignore: -------------------------------------------------------------------------------- 1 | /vendor 2 | /listenparser 3 | /visitorparser 4 | listener_example 5 | visitor_example -------------------------------------------------------------------------------- /Calc.g4: -------------------------------------------------------------------------------- 1 | // Calc.g4 2 | grammar Calc; 3 | 4 | // Tokens 5 | MUL: '*'; 6 | DIV: '/'; 7 | ADD: '+'; 8 | SUB: '-'; 9 | NUMBER: [0-9]+; 10 | WHITESPACE: [ \r\n\t]+ -> skip; 11 | 12 | // Rules 13 | start : expression EOF; 14 | 15 | expression 16 | : expression op=('*'|'/') expression # MulDiv 17 | | expression op=('+'|'-') expression # AddSub 18 | | NUMBER # Number 19 | | '(' expression ')' # Parenthesis 20 | ; 21 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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-------------------------------------------------------------------------------- 1 | .PHONY:all listen visitor 2 | all:listen visitor 3 | listen: 4 | antlr4 -Dlanguage=Go -o listenparser Calc.g4 5 | go build -o listener_example listen/main.go 6 | visitor: 7 | antlr4 -Dlanguage=Go -no-listener -visitor -o visitorparser Calc.g4 8 | go build -o visitor_example visitor/main.go 9 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Antlr4 calulate Example in golang 2 | 3 | ## Install antlr4 4 | 5 | [Install antlr4](https://github.com/antlr/antlr4/blob/master/doc/getting-started.md) 6 | 7 | ### Install antlr4 golang runtime 8 | 9 | ``` 10 | go get github.com/antlr/antlr4/runtime/Go/antlr 11 | ``` 12 | 13 | ## build example 14 | 15 | ``` 16 | make 17 | ./visitor_example 18 | ./listener_example 19 | ``` 20 | 21 | ## reference 22 | 23 | [antlr4-golang](https://blog.gopheracademy.com/advent-2017/parsing-with-antlr4-and-go/) 24 | -------------------------------------------------------------------------------- /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/thesues/antlr-calc-golang-example 2 | 3 | go 1.18 4 | 5 | require github.com/c-bata/go-prompt v0.2.6 6 | 7 | require ( 8 | github.com/antlr/antlr4 v0.0.0-20181218183524-be58ebffde8e 9 | github.com/mattn/go-colorable v0.1.7 // indirect 10 | github.com/mattn/go-isatty v0.0.12 // indirect 11 | github.com/mattn/go-runewidth v0.0.9 // indirect 12 | github.com/mattn/go-tty v0.0.3 // indirect 13 | github.com/pkg/term v1.2.0-beta.2 // indirect 14 | golang.org/x/sys v0.0.0-20200918174421-af09f7315aff // indirect 15 | ) 16 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | github.com/antlr/antlr4 v0.0.0-20181218183524-be58ebffde8e h1:yxMh4HIdsSh2EqxUESWvzszYMNzOugRyYCeohfwNULM= 2 | github.com/antlr/antlr4 v0.0.0-20181218183524-be58ebffde8e/go.mod h1:T7PbCXFs94rrTttyxjbyT5+/1V8T2TYDejxUfHJjw1Y= 3 | github.com/antlr/antlr4/runtime/Go/antlr v1.4.10 h1:yL7+Jz0jTC6yykIK/Wh74gnTJnrGr5AyrNMXuA0gves= 4 | github.com/antlr/antlr4/runtime/Go/antlr v1.4.10/go.mod h1:F7bn7fEU90QkQ3tnmaTx3LTKLEDqnwWODIYppRQ5hnY= 5 | github.com/c-bata/go-prompt v0.2.6 h1:POP+nrHE+DfLYx370bedwNhsqmpCUynWPxuHi0C5vZI= 6 | github.com/c-bata/go-prompt v0.2.6/go.mod h1:/LMAke8wD2FsNu9EXNdHxNLbd9MedkPnCdfpU9wwHfY= 7 | github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE= 8 | github.com/mattn/go-colorable v0.1.7 h1:bQGKb3vps/j0E9GfJQ03JyhRuxsvdAanXlT9BTw3mdw= 9 | github.com/mattn/go-colorable v0.1.7/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc= 10 | github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s= 11 | github.com/mattn/go-isatty v0.0.10/go.mod h1:qgIWMr58cqv1PHHyhnkY9lrL7etaEgOFcMEpPG5Rm84= 12 | github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY= 13 | github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU= 14 | github.com/mattn/go-runewidth v0.0.6/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI= 15 | github.com/mattn/go-runewidth v0.0.9 h1:Lm995f3rfxdpd6TSmuVCHVb/QhupuXlYr8sCI/QdE+0= 16 | github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI= 17 | github.com/mattn/go-tty v0.0.3 h1:5OfyWorkyO7xP52Mq7tB36ajHDG5OHrmBGIS/DtakQI= 18 | github.com/mattn/go-tty v0.0.3/go.mod h1:ihxohKRERHTVzN+aSVRwACLCeqIoZAWpoICkkvrWyR0= 19 | github.com/pkg/term v1.2.0-beta.2 h1:L3y/h2jkuBVFdWiJvNfYfKmzcCnILw7mJWm2JQuMppw= 20 | github.com/pkg/term v1.2.0-beta.2/go.mod h1:E25nymQcrSllhX42Ok8MRm1+hyBdHY0dCeiKZ9jpNGw= 21 | golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= 22 | golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= 23 | golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 24 | golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 25 | golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 26 | golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 27 | golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 28 | golang.org/x/sys v0.0.0-20200918174421-af09f7315aff h1:1CPUrky56AcgSpxz/KfgzQWzfG09u5YOL8MvPYBlrL8= 29 | golang.org/x/sys v0.0.0-20200918174421-af09f7315aff/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= 30 | -------------------------------------------------------------------------------- /listen/main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "fmt" 5 | "strconv" 6 | 7 | "github.com/antlr/antlr4/runtime/Go/antlr" 8 | "github.com/c-bata/go-prompt" 9 | parser "github.com/thesues/antlr-calc-golang-example/listenparser" 10 | ) 11 | 12 | type calcListener struct { 13 | *parser.BaseCalcListener 14 | 15 | stack []int 16 | } 17 | 18 | func (l *calcListener) push(i int) { 19 | l.stack = append(l.stack, i) 20 | 21 | } 22 | 23 | func (l *calcListener) pop() int { 24 | if len(l.stack) < 1 { 25 | panic("stack is empty unable to pop") 26 | } 27 | 28 | // Get the last value from the stack. 29 | result := l.stack[len(l.stack)-1] 30 | 31 | // Remove the last element from the stack. 32 | l.stack = l.stack[:len(l.stack)-1] 33 | 34 | return result 35 | } 36 | 37 | func (l *calcListener) ExitMulDiv(c *parser.MulDivContext) { 38 | right, left := l.pop(), l.pop() 39 | 40 | switch c.GetOp().GetTokenType() { 41 | case parser.CalcParserMUL: 42 | l.push(left * right) 43 | case parser.CalcParserDIV: 44 | l.push(left / right) 45 | default: 46 | panic(fmt.Sprintf("unexpected op: %s", c.GetOp().GetText())) 47 | } 48 | } 49 | 50 | func (l *calcListener) ExitAddSub(c *parser.AddSubContext) { 51 | right, left := l.pop(), l.pop() 52 | 53 | switch c.GetOp().GetTokenType() { 54 | case parser.CalcParserADD: 55 | l.push(left + right) 56 | case parser.CalcParserSUB: 57 | l.push(left - right) 58 | default: 59 | panic(fmt.Sprintf("unexpected op: %s", c.GetOp().GetText())) 60 | } 61 | } 62 | 63 | func (l *calcListener) ExitNumber(c *parser.NumberContext) { 64 | i, err := strconv.Atoi(c.GetText()) 65 | if err != nil { 66 | panic(err.Error()) 67 | } 68 | 69 | l.push(i) 70 | } 71 | 72 | // calc takes a string expression and returns the evaluated result. 73 | func calc(input string) int { 74 | // Setup the input 75 | is := antlr.NewInputStream(input) 76 | 77 | // Create the Lexer 78 | lexer := parser.NewCalcLexer(is) 79 | stream := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel) 80 | 81 | // Create the Parser 82 | p := parser.NewCalcParser(stream) 83 | 84 | // Finally parse the expression (by walking the tree) 85 | var listener calcListener 86 | antlr.ParseTreeWalkerDefault.Walk(&listener, p.Start()) 87 | 88 | return listener.pop() 89 | 90 | } 91 | 92 | func executor(in string) { 93 | fmt.Printf("Answer: %d\n", calc(in)) 94 | } 95 | 96 | func completer(in prompt.Document) []prompt.Suggest { 97 | var ret []prompt.Suggest 98 | return ret 99 | } 100 | 101 | func main() { 102 | p := prompt.New( 103 | executor, 104 | completer, 105 | prompt.OptionPrefix(">>> "), 106 | prompt.OptionTitle("calc"), 107 | ) 108 | p.Run() 109 | } 110 | -------------------------------------------------------------------------------- /visitor/main.go: -------------------------------------------------------------------------------- 1 | //for vistor pattern 2 | package main 3 | 4 | import ( 5 | "fmt" 6 | "strconv" 7 | 8 | "github.com/antlr/antlr4/runtime/Go/antlr" 9 | prompt "github.com/c-bata/go-prompt" 10 | parser "github.com/thesues/antlr-calc-golang-example/visitorparser" 11 | ) 12 | 13 | type Visitor struct { 14 | parser.BaseCalcVisitor 15 | stack []int 16 | } 17 | 18 | func NewVisitor() *Visitor { 19 | return &Visitor{} 20 | } 21 | 22 | func (l *Visitor) push(i int) { 23 | l.stack = append(l.stack, i) 24 | } 25 | 26 | func (l *Visitor) pop() int { 27 | if len(l.stack) < 1 { 28 | panic("stack is empty unable to pop") 29 | } 30 | 31 | // Get the last value from the stack. 32 | result := l.stack[len(l.stack)-1] 33 | 34 | // Remove the last element from the stack. 35 | l.stack = l.stack[:len(l.stack)-1] 36 | 37 | return result 38 | } 39 | 40 | func (v *Visitor) visitRule(node antlr.RuleNode) interface{} { 41 | node.Accept(v) 42 | return nil 43 | } 44 | 45 | func (v *Visitor) VisitStart(ctx *parser.StartContext) interface{} { 46 | return v.visitRule(ctx.Expression()) 47 | } 48 | 49 | func (v *Visitor) VisitNumber(ctx *parser.NumberContext) interface{} { 50 | i, err := strconv.Atoi(ctx.NUMBER().GetText()) 51 | if err != nil { 52 | panic(err.Error()) 53 | } 54 | 55 | v.push(i) 56 | return nil 57 | } 58 | 59 | func (v *Visitor) VisitMulDiv(ctx *parser.MulDivContext) interface{} { 60 | //push expression result to stack 61 | v.visitRule(ctx.Expression(0)) 62 | v.visitRule(ctx.Expression(1)) 63 | 64 | //push result to stack 65 | var t antlr.Token = ctx.GetOp() 66 | right := v.pop() 67 | left := v.pop() 68 | switch t.GetTokenType() { 69 | case parser.CalcParserMUL: 70 | v.push(left * right) 71 | case parser.CalcParserDIV: 72 | v.push(left / right) 73 | default: 74 | panic("should not happen") 75 | 76 | } 77 | 78 | return nil 79 | } 80 | 81 | func (v *Visitor) VisitAddSub(ctx *parser.AddSubContext) interface{} { 82 | //push expression result to stack 83 | v.visitRule(ctx.Expression(0)) 84 | v.visitRule(ctx.Expression(1)) 85 | 86 | //push result to stack 87 | var t antlr.Token = ctx.GetOp() 88 | right := v.pop() 89 | left := v.pop() 90 | switch t.GetTokenType() { 91 | case parser.CalcParserADD: 92 | v.push(left + right) 93 | case parser.CalcParserSUB: 94 | v.push(left - right) 95 | default: 96 | panic("should not happen") 97 | } 98 | 99 | return nil 100 | } 101 | 102 | func (v *Visitor) VisitParenthesis(ctx *parser.ParenthesisContext) interface{} { 103 | v.visitRule(ctx.Expression()) 104 | return nil 105 | } 106 | 107 | func calc(input string) int { 108 | 109 | is := antlr.NewInputStream(input) 110 | 111 | // Create the Lexer 112 | lexer := parser.NewCalcLexer(is) 113 | tokens := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel) 114 | 115 | // Create the Parser 116 | p := parser.NewCalcParser(tokens) 117 | 118 | v := NewVisitor() 119 | //Start is rule name of Calc.g4 120 | p.Start().Accept(v) 121 | return v.pop() 122 | } 123 | 124 | func executor(in string) { 125 | fmt.Printf("Answer: %d\n", calc(in)) 126 | } 127 | 128 | func completer(in prompt.Document) []prompt.Suggest { 129 | var ret []prompt.Suggest 130 | return ret 131 | } 132 | 133 | func main() { 134 | p := prompt.New( 135 | executor, 136 | completer, 137 | prompt.OptionPrefix(">>> "), 138 | prompt.OptionTitle("calc"), 139 | ) 140 | p.Run() 141 | } 142 | --------------------------------------------------------------------------------