add support for scientific notation for digits

gravataLonga · Aug 2, 2022 · 15e26cf · 15e26cf
1 parent 343f184
commit 15e26cf
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Showing 8 changed files with 65 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -139,13 +139,21 @@ puts(a);
   
  100.20;
  5.20;
+ 
+ /**
+  * Scientific Notation  
+  */
+  
+  1e3;
+  2e-3;
   
  /**
   * Strings
   */
    
  "hello"
- "hello \t world \x02\x03"
+ "\u006E\u0069\u006E\u006A\u0061" // ninja in unicode chars  
+ "\n\r\t\b\f" // special caracters is also supported
    
  /**
   * array

diff --git a/evaluator/digit_test.go b/evaluator/digit_test.go
@@ -10,6 +10,22 @@ func TestEvalDigitExpression(t *testing.T) {
 		input    string
 		expected interface{}
 	}{
+		{
+			`1`,
+			1,
+		},
+		{
+			`0.2`,
+			0.2,
+		},
+		{
+			`1e3`,
+			1e3,
+		},
+		{
+			`1e-3`,
+			1e-3,
+		},
 		{
 			`1 + 1`,
 			2,

diff --git a/lexer/lexer.go b/lexer/lexer.go
@@ -190,6 +190,10 @@ func isDigit(ch byte) bool {
 	return '0' <= ch && ch <= '9'
 }
 
+func isScientificNotation(ch byte) bool {
+	return ch == 'e' || ch == 'E'
+}
+
 func (l *Lexer) readIdentifier() []byte {
 	position := l.position
 	for isLetter(l.ch) || isDigit(l.ch) {
@@ -201,8 +205,25 @@ func (l *Lexer) readIdentifier() []byte {
 // readDigit read integer and floats
 func (l *Lexer) readDigit() []byte {
 	position := l.position
-	for isDigit(l.ch) || (l.ch == '.' && isDigit(l.peekChar())) || (l.ch == 'e' && isDigit(l.peekChar())) {
-		l.readChar()
+	isOnScientificNotation := false
+
+	for {
+		if isDigit(l.ch) || (l.ch == '.' && isDigit(l.peekChar())) {
+			l.readChar()
+			continue
+		}
+
+		if l.ch == '-' && isOnScientificNotation {
+			l.readChar()
+			continue
+		}
+
+		if isScientificNotation(l.ch) && !isOnScientificNotation {
+			isOnScientificNotation = true
+			l.readChar()
+			continue
+		}
+		break
 	}
 	return []byte(l.input[position:l.position])
 }

diff --git a/lexer/lexer_test.go b/lexer/lexer_test.go
@@ -249,6 +249,11 @@ func TestLexerReadNumber(t *testing.T) {
 			`1`,
 			token.INT,
 		},
+		{
+			`2`,
+			`2`,
+			token.INT,
+		},
 		{
 			`1234`,
 			`1234`,
@@ -267,7 +272,12 @@ func TestLexerReadNumber(t *testing.T) {
 		{
 			`1e3`,
 			`1e3`,
-			token.INT,
+			token.FLOAT,
+		},
+		{
+			`1e-3`,
+			`1e-3`,
+			token.FLOAT,
 		},
 	}
 

diff --git a/parser/infix.go b/parser/infix.go
@@ -5,7 +5,7 @@ import "github.com/gravataLonga/ninja/ast"
 func (p *Parser) parseInfixExpression(left ast.Expression) ast.Expression {
 	expression := &ast.InfixExpression{
 		Token:    p.curToken,
-		Operator: string(p.curToken.Literal),
+		Operator: p.curToken.Literal,
 		Left:     left,
 	}
 

diff --git a/parser/integer.go b/parser/integer.go
@@ -8,7 +8,7 @@ import (
 func (p *Parser) parseIntegerLiteral() ast.Expression {
 	lit := &ast.IntegerLiteral{Token: p.curToken}
 
-	value, err := strconv.ParseInt(string(p.curToken.Literal), 0, 64)
+	value, err := strconv.ParseInt(p.curToken.Literal, 0, 64)
 	if err != nil {
 		p.newError("could not parse %q as integer", p.curToken.Literal)
 		return nil

diff --git a/parser/string.go b/parser/string.go
@@ -3,5 +3,5 @@ package parser
 import "github.com/gravataLonga/ninja/ast"
 
 func (p *Parser) parseString() ast.Expression {
-	return &ast.StringLiteral{Token: p.curToken, Value: string(p.curToken.Literal)}
+	return &ast.StringLiteral{Token: p.curToken, Value: p.curToken.Literal}
 }
diff --git a/token/token.go b/token/token.go
@@ -186,8 +186,9 @@ func LookupIdentifier(ident []byte) TokenType {
 // for now we only support integer and float, but later we
 // need to support Hex and Octa. @todo
 func DigitType(digit []byte) TokenType {
-	hasDot := bytes.IndexByte(digit, '.')
-	if hasDot >= 0 {
+	hasDot := bytes.IndexByte(digit, '.') >= 0
+	hasENotation := bytes.IndexByte(digit, 'e') >= 0 || bytes.IndexByte(digit, 'E') >= 0
+	if hasDot || hasENotation {
 		return FLOAT
 	}
 	return INT