pj1-go/ast-print.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func print(expr Expr) string {
+	switch e := expr.(type) {
+	case Binary:
+		return parenthesize(e.operator.Lexeme,
+			e.left,
+			e.right)
+	case Grouping:
+		return parenthesize("group", e.expression)
+	case Literal:
+		if e.value == nil {
+			return "nil"
+		}
+		return fmt.Sprintf("%v", e.value)
+	case Unary:
+		return parenthesize(e.operator.Lexeme, e.right)
+	}
+	return "ERROR: reached impossible branch in print function"
+}
+
+func parenthesize(name string, exprs ...Expr) string {
+	var sb strings.Builder
+
+	sb.WriteString("(" + name)
+
+	for _, expr := range exprs {
+		sb.WriteString(" ")
+		sb.WriteString(print(expr))
+	}
+	sb.WriteString(")")
+
+	return sb.String()
+}
+
+// This was briefly a testing function for the AST class at the end of ch. 5
+/*
+func main() {
+	var expression Expr = Binary{
+		Unary{
+			lexer.NewToken(lexer.MINUS, "-", nil, 1),
+			Literal{123},
+		},
+		lexer.NewToken(lexer.STAR, "*", nil, 1),
+		Grouping{
+			Literal{45.67},
+		},
+	}
+	fmt.Println(print(expression))
+}
+*/

pj1-go/gen-ast.go

@@ -1,4 +1,5 @@
 //go:build generate
+
 //go:generate go run ./gen-ast.go ./
 
 package main
@@ -48,6 +49,7 @@ func main() {
 		[]string{"Binary : left Expr, operator lexer.Token, right Expr",
 			"Grouping : expression Expr",
 			"Literal : value interface{}",
+			// a literal can be any value that can be printed
 			"Unary : operator lexer.Token, right Expr"})
 }
 
@@ -72,7 +74,7 @@ func defineAst(outputDir string, baseName string, types []string) {
 	fmt.Fprintln(f, "// Code generated by tools/gen-ast.go DO NOT EDIT.")
 	fmt.Fprintln(f, "package main")
 	fmt.Fprintln(f)
-	fmt.Fprintln(f, "import \"" + modulePath + "/lexer\"")
+	fmt.Fprintln(f, "import \""+modulePath+"/lexer\"")
 	fmt.Fprintln(f)
 	// Creates a dummy interface just to limit types which can be
 	// considered an "Expr"
@@ -91,19 +93,19 @@ func defineAst(outputDir string, baseName string, types []string) {
 }
 
 func defineType(f io.Writer, baseName string, typeName string, fieldList string) {
-	fmt.Fprintln(f, "type " + typeName + " struct {")
+	fmt.Fprintln(f, "type "+typeName+" struct {")
 
 	// Fields.
 	var fields []string = strings.Split(fieldList, ", ")
 	for _, field := range fields {
-		fmt.Fprintln(f, "\t" + field)
+		fmt.Fprintln(f, "\t"+field)
 	}
 
 	fmt.Fprintln(f, "}")
 	fmt.Fprintln(f)
 
 	// Interface dummy function
-	fmt.Fprintln(f, "func (x "+typeName+") is"+ baseName +"() {}")
+	fmt.Fprintln(f, "func (x "+typeName+") is"+baseName+"() {}")
 	fmt.Fprintln(f)
 
 	// TODO: may have to generate constructor, according to top of

pj1-go/go.sum

@@ -1,3 +1,5 @@
+git.bonsai.cool/kayprish/pj1/pj1-go v0.0.0-20240807135935-04e669c15630 h1:SO1oOi4BAVPmoCkBCeZEcNXiCDZJrM49Y5Fhm/bBuBU=
+git.bonsai.cool/kayprish/pj1/pj1-go v0.0.0-20240807135935-04e669c15630/go.mod h1:f4dHsvhBf6lTSjuA+gqssxFOHdkOjPnS4QeufMWvHOM=
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9wrfxYyCjk0KbXjhR55s=

pj1-go/lexer/lexer.go

@@ -88,7 +88,7 @@ var keywords = map[string]TokenType{
 
 type Token struct {
 	ttype   TokenType
-	lexeme  string
+	Lexeme  string
 	literal interface{}
 	line    int
 }
@@ -99,7 +99,7 @@ func NewToken(ttype TokenType, lexeme string, literal interface{}, line int) Tok
 }
 
 func (t Token) String() string {
-	return fmt.Sprintf("%v %v %v", t.ttype, t.lexeme, t.literal)
+	return fmt.Sprintf("%v %v %v", t.ttype, t.Lexeme, t.literal)
 }
 
 type Lexer struct {

pj1-go/pj1.go

@@ -10,16 +10,16 @@ import (
 	"git.bonsai.cool/kayprish/pj1/pj1-go/util"
 )
 
-func main() {
-	if len(os.Args) > 2 {
-		fmt.Println("Usage: pj1-go [script]")
-		os.Exit(64)
-	} else if len(os.Args) == 2 {
-		runFile(os.Args[0])
-	} else {
-		runPrompt()
-	}
-}
+// func main() {
+// 	if len(os.Args) > 2 {
+// 		fmt.Println("Usage: pj1-go [script]")
+// 		os.Exit(64)
+// 	} else if len(os.Args) == 2 {
+// 		runFile(os.Args[0])
+// 	} else {
+// 		runPrompt()
+// 	}
+// }
 
 func runFile(path string) {
 	bytes, err := ioutil.ReadFile(path)