Moved run to main and fixed binary parsing bug

README.md

@@ -13,7 +13,7 @@ This roadmap highlights progress for Fizz's development:
 - ✔️ Expression parsing
 - ✔️ Conditional statements
 - ✔️ Loops
-- ❌ Functions
+- ✔️ Functions
 - ❌ Classes
 - ❌ Arrays
 - ❌ File import

expr/parse.go

@@ -181,6 +181,14 @@ func parsePTokens(tokens []ParseToken) *Expression {
 		}
 	}
 
+	// Invalid expression might have lowest as end token
+	// Move to middle and let evaluation handle error
+	if lowestIdx == len(tokens) - 1 {
+		newIdx := int(len(tokens)/2)
+		lowestIdx = newIdx
+		lowest = tokens[lowestIdx].Token
+	}
+
 	right, left := parsePTokens(tokens[lowestIdx+1:]), parsePTokens(tokens[:lowestIdx])
 	return &Expression{Type: Binary, Line: line, Operand: lowest, Left: left, Right: right}
 }

go.mod

@@ -1,3 +1,5 @@
 module github.com/jesperkha/Fizz
 
 go 1.16
+
+require github.com/daviddengcn/go-colortext v1.0.0

go.sum

@@ -0,0 +1,7 @@
+github.com/daviddengcn/go-colortext v1.0.0 h1:ANqDyC0ys6qCSvuEK7l3g5RaehL/Xck9EX8ATG8oKsE=
+github.com/daviddengcn/go-colortext v1.0.0/go.mod h1:zDqEI5NVUop5QPpVJUxE9UO10hRnmkD5G4Pmri9+m4c=
+github.com/golangplus/bytes v0.0.0-20160111154220-45c989fe5450/go.mod h1:Bk6SMAONeMXrxql8uvOKuAZSu8aM5RUGv+1C6IJaEho=
+github.com/golangplus/bytes v1.0.0/go.mod h1:AdRaCFwmc/00ZzELMWb01soso6W1R/++O1XL80yAn+A=
+github.com/golangplus/fmt v1.0.0/go.mod h1:zpM0OfbMCjPtd2qkTD/jX2MgiFCqklhSUFyDW44gVQE=
+github.com/golangplus/testing v1.0.0 h1:+ZeeiKZENNOMkTTELoSySazi+XaEhVO0mb+eanrSEUQ=
+github.com/golangplus/testing v1.0.0/go.mod h1:ZDreixUV3YzhoVraIDyOzHrr76p6NUh6k/pPg/Q3gYA=

run/interp.go → interp.go

@@ -1,4 +1,4 @@
-package run
+package main
 
 import (
 	"github.com/jesperkha/Fizz/lexer"

main.go

@@ -2,10 +2,8 @@ package main
 
 import (
 	"os"
-
-	"github.com/jesperkha/Fizz/run"
 )
 
 func main() {
-	run.RunInterpeter(os.Args)
+	RunInterpeter(os.Args)
 }

run.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	ct "github.com/daviddengcn/go-colortext"
+)
+
+var (
+	ErrFileNotFound = errors.New("cannot find file with name: '%s'")
+	ErrNonFizzFile  = errors.New("cannot run non-Fizz file")
+)
+
+var cmdOptions = map[string]func(){
+	"help": func() {
+		fmt.Println("use: fizz [filename.fizz | --option]")
+	},
+}
+
+func RunInterpeter(args []string) {
+	if len(args) == 2 {
+		arg := args[1]
+
+		// Run option commands
+		if strings.HasPrefix(arg, "--") {
+			option, ok := cmdOptions[strings.TrimLeft(arg, "-")]
+			if !ok {
+				formatError(fmt.Errorf("unknown option: '%s'", arg))
+				return
+			}
+
+			option()
+		}
+
+		// Run fizz file
+		filename := args[1]
+		if !strings.HasSuffix(filename, ".fizz") {
+			filename += ".fizz"
+		}
+
+		if err := runFile(filename); err != nil {
+			formatError(err)
+		}
+
+		return
+	}
+
+	// Run terminal mode
+	runTerminal()
+}
+
+// Prints errors with red color to terminal
+func formatError(err error) {
+	ct.Foreground(ct.Red, true)
+	fmt.Println(err.Error())
+	ct.ResetColor()
+}
+
+// Leaves the interpreter running as the user inputs code to the terminal.
+// Prints out errors but does not terminate until ^C or 'exit'.
+func runTerminal() {
+	scanner := bufio.NewScanner(os.Stdin)
+	totalString := ""
+	numBlocks := 0
+	indent := "    "
+
+	fmt.Println("type 'exit' to terminate session")
+	for {
+		fmt.Print("::: " + strings.Repeat(indent, numBlocks))
+		scanner.Scan()
+		input := scanner.Text()
+
+		if input == "exit" {
+			break
+		}
+
+		// Continue with indent after braces
+		numBlocks += strings.Count(input, "{") - strings.Count(input, "}")
+		totalString += input + "\n" // Better error handling
+
+		if numBlocks <= 0 {
+			err := Interperate(totalString)
+			if err != nil {
+				formatError(err)
+			}
+
+			totalString = ""
+			numBlocks = 0
+		}
+	}
+
+	fmt.Println("session ended")
+}
+
+// Interperates code found in file specified in commandline arguments
+func runFile(filename string) (err error) {
+	if !strings.HasSuffix(filename, ".fizz") {
+		return ErrNonFizzFile
+	}
+
+	if file, err := os.Open(filename); err == nil {
+		var buf bytes.Buffer
+		bufio.NewReader(file).WriteTo(&buf)
+		return Interperate(buf.String())
+	}
+
+	// Assumes path error
+	return fmt.Errorf(ErrFileNotFound.Error(), filename)
+}

stmt/parse.go

@@ -191,21 +191,22 @@ func parseFunc(tokens []lexer.Token, idx *int) (stmt Statement, err error) {
 	if len(tokens) < 6 {
 		return stmt, ErrInvalidStatement
 	}
-
+	
 	nameToken := tokens[*idx+1]
 	if nameToken.Type != lexer.IDENTIFIER || tokens[*idx+2].Type != lexer.LEFT_PAREN {
 		return stmt, ErrInvalidStatement // Missing identifier or block
 	}
-
+	
 	*idx += 3 // Skip to start of param list
 	endIdx, eof := seekToken(tokens, *idx, lexer.RIGHT_PAREN)
 	if eof {
 		return stmt, ErrInvalidStatement
 	}
-
+	
 	// Get param names
 	params := []string{}
 	for _, p := range tokens[*idx:endIdx] {
+		// Todo: Add actual comma separation for function declarations
 		switch p.Type {
 		case lexer.COMMA:
 			continue