added scientific notation

AUTHORS

@@ -13,4 +13,5 @@ Raymond Sohn <raymondsohn@gmail.com>
 Thorbjørn Lindeijer <bjorn@lindeijer.nl>
 Patricio Mac Adden <patriciomacadden@gmail.com>
 Evan Hahn <me@evanhahn.com>
-Starbeamrainbowlabs <contact@starbeamrainbowlabs.com>
+Starbeamrainbowlabs <contact@starbeamrainbowlabs.com>
+Alexander Roper <minirop@gmail.com>

src/vm/wren_compiler.c

@@ -608,7 +608,6 @@ static void readHexNumber(Parser* parser)
 // Finishes lexing a number literal.
 static void readNumber(Parser* parser)
 {
-  // TODO: scientific, etc.
   while (isDigit(peekChar(parser))) nextChar(parser);
 
   // See if it has a floating point. Make sure there is a digit after the "."
@@ -618,6 +617,22 @@ static void readNumber(Parser* parser)
     nextChar(parser);
     while (isDigit(peekChar(parser))) nextChar(parser);
   }
+  
+  // See if the number is in scientific notation
+  if (peekChar(parser) == 'e' || peekChar(parser) == 'E')
+  {
+    nextChar(parser);
+    
+    // if the exponant is negative
+    if(peekChar(parser) == '-') nextChar(parser);
+    
+    if(!isDigit(peekChar(parser)))
+    {
+      lexError(parser, "Unterminated scientific notation.");
+    }
+    
+    while (isDigit(peekChar(parser))) nextChar(parser);
+  }
 
   makeNumber(parser, false);
 }

test/language/number/literals.wren

@@ -6,5 +6,4 @@ IO.print(-0)      // expect: -0
 IO.print(123.456) // expect: 123.456
 IO.print(-0.001)  // expect: -0.001
 
-// TODO: Scientific notation?
 // TODO: Literals at and beyond numeric limits.

test/language/number/scientific_float_missing_exponent.wren

@@ -0,0 +1 @@
+var x = 1.2e // expect error

test/language/number/scientific_floating_exponant.wren

@@ -0,0 +1 @@
+var x = 1.2e3.4 // expect error

test/language/number/scientific_literals.wren

@@ -0,0 +1,9 @@
+var x = 2.55e2
+
+IO.print(x) // expect: 255
+IO.print(x + 1) // expect: 256
+IO.print(x == 255) // expect: true
+IO.print(2.55e-2 is Num) // expect: true
+IO.print(x is Num) // expect: true
+IO.print(-2.55e2) // expect: -255
+IO.print(-25500e-2) // expect: -255

test/language/number/scientific_missing_exponent.wren

@@ -0,0 +1 @@
+var x = 1e // expect error

test/language/number/scientific_missing_fractional_part.wren

@@ -0,0 +1 @@
+var x = 1.e // expect runtime error: Num does not implement 'e'.

test/language/number/scientific_multiple_exponants.wren

@@ -0,0 +1 @@
+var x = 1.2e3e4 // expect error