Compare commits
No commits in common. "6403c4578c4f5c79f1f292d831d161b8fc4692cc" and "475b15522813a979b256fa8081082175d345c7d8" have entirely different histories.
6403c4578c
...
475b155228
10
expr_grammar
10
expr_grammar
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@ -1,10 +0,0 @@
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expression -> equality ;
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equality -> comparison ( ( "!=" | "==" ) comparison )* ;
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comparison -> term ( ( ">" | ">=" | "<" | "<=" ) term )* ;
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term -> factor ( ( "-" | "+" ) factor )* ;
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factor -> exponent ( ( "/" | "*" | "/." | "/_" | "%" | "/%" ) exponent )* ;
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exponent -> unary ( ( "**" ) unary )* ;
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unary -> ( "!" | "-" ) unary
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| primary ;
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primary -> NUMBER | STRING | "true" | "false" | "nil"
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| "(" expression ")" ;
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@ -1,22 +0,0 @@
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package main
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import (
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"fmt"
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)
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func rpn(expr Expr) string {
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switch e := expr.(type) {
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case Binary:
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return rpn(e.left) + " " + rpn(e.right) + " " + e.operator.Lexeme
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case Grouping:
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return rpn(e.expression) // + " group" arguable if this is even wanted
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case Literal:
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if e.value == nil {
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return "nil"
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}
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return fmt.Sprintf("%v", e.value)
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case Unary:
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return rpn(e.right) + fmt.Sprintf(" %v", e.operator.Lexeme)
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}
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return "ERROR: reached impossible branch in print function"
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}
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@ -1,13 +1,15 @@
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// Code generated by tools/gen-ast.go DO NOT EDIT.
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package main
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import "git.bonsai.cool/kayprish/pj1/pj1-go/lexer"
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type Expr interface {
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isExpr()
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}
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type Binary struct {
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left Expr
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operator Token
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operator lexer.Token
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right Expr
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}
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@ -26,7 +28,7 @@ type Literal struct {
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func (x Literal) isExpr() {}
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type Unary struct {
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operator Token
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operator lexer.Token
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right Expr
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}
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@ -14,11 +14,10 @@ import (
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"unicode/utf8"
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)
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var modulePath string
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// returns a string which contains the current module path, keep in mind this
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// program is meant to be run in the root of the module using go generate
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//
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// This function is no longer useful because the lexer package has been
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// deleted, however, it may become useful again soon
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func getModulePath() string {
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goModFile, err := os.Open("./go.mod")
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if err != nil {
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@ -45,12 +44,13 @@ func main() {
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os.Exit(64)
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}
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outputDir := os.Args[1]
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modulePath = getModulePath()
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defineAst(outputDir, "Expr",
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[]string{"Binary : left Expr, operator Token, right Expr",
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[]string{"Binary : left Expr, operator lexer.Token, right Expr",
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"Grouping : expression Expr",
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"Literal : value interface{}",
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// a literal can be any value that can be printed
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"Unary : operator Token, right Expr"})
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"Unary : operator lexer.Token, right Expr"})
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}
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func lowerFirst(s string) string {
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@ -74,6 +74,8 @@ func defineAst(outputDir string, baseName string, types []string) {
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fmt.Fprintln(f, "// Code generated by tools/gen-ast.go DO NOT EDIT.")
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fmt.Fprintln(f, "package main")
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fmt.Fprintln(f)
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fmt.Fprintln(f, "import \""+modulePath+"/lexer\"")
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fmt.Fprintln(f)
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// Creates a dummy interface just to limit types which can be
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// considered an "Expr"
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fmt.Fprintln(f, "type "+baseName+" interface {")
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@ -1,13 +1,10 @@
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module git.bonsai.cool/kayprish/pj1/pj1-go
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go 1.22.0
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go 1.18
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toolchain go1.22.2
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require golang.org/x/tools v0.29.0
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require golang.org/x/tools v0.1.13-0.20220917004541-4d18923f060e
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require (
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golang.org/x/mod v0.22.0 // indirect
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golang.org/x/sync v0.10.0 // indirect
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golang.org/x/sys v0.29.0 // indirect
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golang.org/x/mod v0.12.0 // indirect
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golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect
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)
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@ -1,14 +1,8 @@
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git.bonsai.cool/kayprish/pj1/pj1-go v0.0.0-20240807135935-04e669c15630 h1:SO1oOi4BAVPmoCkBCeZEcNXiCDZJrM49Y5Fhm/bBuBU=
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git.bonsai.cool/kayprish/pj1/pj1-go v0.0.0-20240807135935-04e669c15630/go.mod h1:f4dHsvhBf6lTSjuA+gqssxFOHdkOjPnS4QeufMWvHOM=
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golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
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golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
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golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=
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golang.org/x/mod v0.22.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
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golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
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golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
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golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9wrfxYyCjk0KbXjhR55s=
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golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
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golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
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golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
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golang.org/x/tools v0.1.13-0.20220917004541-4d18923f060e h1:K/LreqAwv7hZaSPyj5LvaiQd2wROouJDabf2r+oBqUw=
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golang.org/x/tools v0.1.13-0.20220917004541-4d18923f060e/go.mod h1:VsjNM1dMo+Ofkp5d7y7fOdQZD8MTXSQ4w3EPk65AvKU=
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golang.org/x/tools v0.29.0 h1:Xx0h3TtM9rzQpQuR4dKLrdglAmCEN5Oi+P74JdhdzXE=
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golang.org/x/tools v0.29.0/go.mod h1:KMQVMRsVxU6nHCFXrBPhDB8XncLNLM0lIy/F14RP588=
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@ -1,4 +1,4 @@
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package main
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package lexer
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import (
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"fmt"
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@ -23,10 +23,9 @@ const (
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MINUS
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PLUS
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SEMICOLON
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STAR
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// One or two character tokens.
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STAR
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STAR_STAR
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BANG
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BANG_EQUAL
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EQUAL
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@ -38,8 +37,6 @@ const (
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SLASH
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SLASH_DOT
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SLASH_UNDERSCORE
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SLASH_MODULO
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MODULO
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// Literals
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IDENTIFIER
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@ -157,11 +154,6 @@ func (l *Lexer) scanToken() {
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case ';':
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l.addSimpleToken(SEMICOLON)
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case '*':
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if l.match('*') {
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l.addSimpleToken(STAR_STAR)
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} else {
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l.addSimpleToken(STAR)
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}
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l.addSimpleToken(STAR)
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case '!':
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if l.match('=') {
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@ -187,8 +179,6 @@ func (l *Lexer) scanToken() {
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} else {
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l.addSimpleToken(GREATER)
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}
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case '%':
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l.addSimpleToken(MODULO)
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case '/':
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if l.match('/') {
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// A comment goes until the end of the line
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@ -221,8 +211,6 @@ func (l *Lexer) scanToken() {
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l.addSimpleToken(SLASH_DOT)
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} else if l.match('_') {
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l.addSimpleToken(SLASH_UNDERSCORE)
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} else if l.match('%') {
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l.addSimpleToken(SLASH_MODULO)
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} else {
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l.addSimpleToken(SLASH)
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}
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@ -1,6 +1,6 @@
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// Code generated by "stringer -type=TokenType"; DO NOT EDIT.
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package main
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package lexer
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import "strconv"
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@ -29,34 +29,32 @@ func _() {
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_ = x[SLASH-18]
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_ = x[SLASH_DOT-19]
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_ = x[SLASH_UNDERSCORE-20]
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_ = x[SLASH_MODULO-21]
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_ = x[MODULO-22]
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_ = x[IDENTIFIER-23]
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_ = x[STRING-24]
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_ = x[INTEGER-25]
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_ = x[FLOAT-26]
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_ = x[AND-27]
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_ = x[CLASS-28]
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_ = x[ELSE-29]
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_ = x[FALSE-30]
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_ = x[FOR-31]
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_ = x[FUN-32]
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_ = x[IF-33]
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_ = x[NIL-34]
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_ = x[OR-35]
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_ = x[PRINT-36]
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_ = x[RETURN-37]
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_ = x[SUPER-38]
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_ = x[THIS-39]
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_ = x[TRUE-40]
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_ = x[VAR-41]
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_ = x[WHILE-42]
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_ = x[EOF-43]
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_ = x[IDENTIFIER-21]
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_ = x[STRING-22]
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_ = x[INTEGER-23]
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_ = x[FLOAT-24]
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_ = x[AND-25]
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_ = x[CLASS-26]
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_ = x[ELSE-27]
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_ = x[FALSE-28]
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_ = x[FOR-29]
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_ = x[FUN-30]
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_ = x[IF-31]
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_ = x[NIL-32]
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_ = x[OR-33]
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_ = x[PRINT-34]
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_ = x[RETURN-35]
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_ = x[SUPER-36]
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_ = x[THIS-37]
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_ = x[TRUE-38]
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_ = x[VAR-39]
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_ = x[WHILE-40]
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_ = x[EOF-41]
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}
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const _TokenType_name = "LEFT_PARENRIGHT_PARENLEFT_BRACERIGHT_BRACECOMMADOTMINUSPLUSSEMICOLONSTARBANGBANG_EQUALEQUALEQUAL_EQUALGREATERGREATER_EQUALLESSLESS_EQUALSLASHSLASH_DOTSLASH_UNDERSCORESLASH_MODULOMODULOIDENTIFIERSTRINGINTEGERFLOATANDCLASSELSEFALSEFORFUNIFNILORPRINTRETURNSUPERTHISTRUEVARWHILEEOF"
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const _TokenType_name = "LEFT_PARENRIGHT_PARENLEFT_BRACERIGHT_BRACECOMMADOTMINUSPLUSSEMICOLONSTARBANGBANG_EQUALEQUALEQUAL_EQUALGREATERGREATER_EQUALLESSLESS_EQUALSLASHSLASH_DOTSLASH_UNDERSCOREIDENTIFIERSTRINGINTEGERFLOATANDCLASSELSEFALSEFORFUNIFNILORPRINTRETURNSUPERTHISTRUEVARWHILEEOF"
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var _TokenType_index = [...]uint16{0, 10, 21, 31, 42, 47, 50, 55, 59, 68, 72, 76, 86, 91, 102, 109, 122, 126, 136, 141, 150, 166, 178, 184, 194, 200, 207, 212, 215, 220, 224, 229, 232, 235, 237, 240, 242, 247, 253, 258, 262, 266, 269, 274, 277}
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var _TokenType_index = [...]uint16{0, 10, 21, 31, 42, 47, 50, 55, 59, 68, 72, 76, 86, 91, 102, 109, 122, 126, 136, 141, 150, 166, 176, 182, 189, 194, 197, 202, 206, 211, 214, 217, 219, 222, 224, 229, 235, 240, 244, 248, 251, 256, 259}
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func (i TokenType) String() string {
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if i < 0 || i >= TokenType(len(_TokenType_index)-1) {
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@ -6,19 +6,20 @@ import (
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"io/ioutil"
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"os"
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"git.bonsai.cool/kayprish/pj1/pj1-go/lexer"
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"git.bonsai.cool/kayprish/pj1/pj1-go/util"
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)
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func main() {
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if len(os.Args) > 2 {
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fmt.Println("Usage: pj1-go [script]")
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os.Exit(64)
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} else if len(os.Args) == 2 {
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runFile(os.Args[0])
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} else {
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runPrompt()
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}
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}
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// func main() {
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// if len(os.Args) > 2 {
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// fmt.Println("Usage: pj1-go [script]")
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// os.Exit(64)
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// } else if len(os.Args) == 2 {
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// runFile(os.Args[0])
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// } else {
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// runPrompt()
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// }
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// }
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func runFile(path string) {
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bytes, err := ioutil.ReadFile(path)
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@ -52,9 +53,9 @@ func runPrompt() {
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}
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func run(source string) {
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l := NewLexer(source)
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l := lexer.NewLexer(source)
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l.ScanTokens()
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var tokens []Token = l.Tokens
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var tokens []lexer.Token = l.Tokens
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for _, token := range tokens {
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fmt.Println(token)
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|
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@ -1,43 +0,0 @@
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Chapter 5, challenge 1:
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Earlier, I said that the | , * , and + forms we added to our grammar metasyntax
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were just syntactic sugar. Take this grammar:
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expr → expr ( "(" ( expr ( "," expr )* )? ")" | "." IDENTIFIER )+
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| IDENTIFIER
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| NUMBER
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Produce a grammar that matches the same language but does not use any of the notational sugar.
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solution:
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expr -> IDENTIFIER
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expr -> NUMBER
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expr -> expr callOrIndex
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callOrIndex -> "." IDENTIFIER
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callOrIndex -> "(" call ")"
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call ->
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call -> expr
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call -> expr callListEnd
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callListEnd ->
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callListEnd -> "," expr precedingCommaCall
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The grammar here clearly describes a number, or an identifier to a number, or a
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function call, or a structure access
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|
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Chapter 5, challenge 2:
|
||||
The Visitor pattern lets you emulate the functional style in an object-oriented
|
||||
language. Devise a complementary pattern for a functional language. It should let
|
||||
you bundle all of the operations on one type together and let you define new types
|
||||
easily.
|
||||
(SML or Haskell would be ideal for this exercise, but Scheme or another Lisp works
|
||||
as well.)
|
||||
|
||||
solution:
|
||||
Here, we're supposed to be able to define a new type that "inherits" an
|
||||
existing one and bundle all the function implementations on that type together.
|
||||
We could simply write the functions by specific type in one place, since Haskell is just that flexible, but that doesn't guarrantee we wrote the needed functions.
|
||||
Another thing we could do is to put all necessary functions in a single structure, and define a type for this structure, for example if our supertype is Expr, with functions like "printInStr", "execute" and "optimize", our function bundle would look like:
|
||||
data ExprFuncs a = ExprFuncs (a -> str) (a -> IO ()) (a -> Expr)
|
Loading…
Reference in a new issue