Add true/false, strings

mshell-go/Evaluator.go

@@ -148,6 +148,16 @@ func (state EvalState) Evaluate(tokens []Token, stack *MShellStack, context Exec
             if t.Type == QUESTION {
                 stack.Push(&MShellInt { exitCode })
             }
+        } else if t.Type == TRUE {
+            stack.Push(&MShellBool { true })
+        } else if t.Type == FALSE {
+            stack.Push(&MShellBool { false })
+        } else if t.Type == STRING {
+            parsedString, err := ParseRawString(t.Lexeme)
+            if err != nil {
+                return FailWithMessage(fmt.Sprintf("%d:%d: Error parsing string: %s\n", t.Line, t.Column, err.Error()))
+            }
+            stack.Push(&MShellString { parsedString })
         } else {
             return FailWithMessage(fmt.Sprintf("%d:%d: We haven't implemented the token type '%s' yet.\n", t.Line, t.Column, t.Type))
         }

mshell-go/MShellObject.go

@@ -4,6 +4,7 @@ import (
     "io"
     "strconv"
     "strings"
+    "fmt"
 )
 
 type MShellObject interface {
@@ -240,3 +241,46 @@ func (obj *MShellPipe) DebugString() string {
 func (obj *MShellInt) DebugString() string {
     return strconv.Itoa(obj.Value)
 }
+
+func ParseRawString(inputString string) (string, error) {
+    // Purpose of this function is to remove outer quotes, handle escape characters
+    if len(inputString) < 2 {
+        return "", fmt.Errorf("input string should have a minimum length of 2 for surrounding double quotes")
+    }
+
+    var b strings.Builder
+	index := 1
+	inEscape := false
+
+	for index < len(inputString) - 1 {
+		c := inputString[index]
+
+		if inEscape {
+			switch c {
+			case 'n':
+				b.WriteRune('\n')
+			case 't':
+				b.WriteRune('\t')
+			case 'r':
+				b.WriteRune('\r')
+			case '\\':
+				b.WriteRune('\\')
+			case '"':
+				b.WriteRune('"')
+			default:
+				return "", fmt.Errorf("invalid escape character '%c'", c)
+			}
+			inEscape = false
+		} else {
+			if c == '\\' {
+				inEscape = true
+			} else {
+				b.WriteRune(rune(c))
+			}
+		}
+
+		index++
+	}
+
+	return b.String(), nil
+}