ternary expressions added. seem ok

exp.lox

@@ -0,0 +1,4 @@
+(13 > (5 * 3 + 9));
+123 != 12312 + (2.3 == 123) * 9.12
+// asf asf
+1+2-3*4/5  //  saywha

expressions.py

@@ -32,6 +32,12 @@ class Unary(Expr):
 class Variable(Expr):
 	name: Token  #identifier
 
+@dataclass
+class Ternary(Expr):
+	comparison: Expr
+	left: Expr  # true evaluation, comparison must be boolean
+	right: Expr
+
 
 class AstPrinter(Visitor):
 	"""only good at printing out (and making strings) from binary expressions"""
@@ -65,6 +71,8 @@ def visitUnary(self, expr):
 	def visitBinary(self, expr):
 		return self.parensiffy(expr.op.lexeme, expr.left, expr.right)
 
+	def visitTernary(self, expr):
+		return f'if [{expr.comparison}]; then [{expr.left}]; else [{expr.right}]'
 	"""
 	def visitExpr(self, expr):
 		return self.parensiffy(expr.expr)

interpreter.py

@@ -25,6 +25,13 @@ def visitStmtPrint(self, stmt):
 		print(val)
 		return val
 
+	def visitStmtVar(self, stmt):
+		"""
+		stmt.name
+		stmt.initializer
+		"""
+		...
+
 	def visitLiteral(self, expr):
 		return expr.value
 

parser.py

@@ -87,7 +87,9 @@ class Parser(ParserNav):
 	exprStmt       → expression ";" ;
 	printStmt      → "print" expression ";" ;
 
-	expression     → equality ;
+	expression     → equality |
+	                 ternary ;
+	ternary        → equality "?" expression ":" expression ;
 	equality       → comparison ( ( "!=" | "==" ) comparison )* ;
 	comparison     → term ( ( ">" | ">=" | "<" | "<=" ) term )* ;
 	term           → factor ( ( "-" | "+" ) factor )* ;
@@ -97,7 +99,7 @@ class Parser(ParserNav):
 	primary        → NUMBER | STRING | "true" | "false" | "nil"
 	               | "(" expression ")"
 	               | IDENTIFIER ;
-   """
+	"""
 
 	def __init__(self, tokens: list[Token]):
 		self.tokens = tokens
@@ -147,12 +149,29 @@ def printStmt(self):
 
 	def expressionStmt(self):
 		val = self.expression()
-		assert isinstance(val, Expr)
+
+		# if val is None:
+			# val = Expr()
+			# next assert is now guaranteed... lame
+		assert isinstance(val, (Stmt, Expr)), f"{val}. repr: `"+repr(val)+"`"
+
 		self.consume(TokenType.SEMICOLON, "expected a ';' after expressionStmt. where is my  ; !?")
 		return StmtExpr(val)
 
 	def expression(self):
-		return self.equality()
+		"""
+		expression → equality |
+		             ternary ;
+		"""
+		eq = self.equality()
+
+		if self.match(TokenType.QUESTION):
+			left = self.expression()
+			self.consume(TokenType.COLON, "Expected ':' for a ternary expr.")
+			right = self.expression()
+			return Ternary(eq, left, right)
+		else:
+			return eq
 
 	def equality(self):
 		expr = self.comparison()

scanner.py

@@ -35,6 +35,9 @@ class TokenType(Enum):
 	LESS = '<'
 	LESS_EQUAL = '<='
 
+	QUESTION = '?'
+	COLON = ':'
+
 	# // Literals.
 	IDENTIFIER = auto()
 	STRING = auto()

src.lox

@@ -1,6 +1,8 @@
-// sample, should write a real program.
-() [] [   ] ([]) (])
-"strings"
-123
-123.1233
 var language = "lox";
+var test =
+	1 == 2 ? "help" : "we cool, no help";
+
+
+"strings";
+123;
+123.1233; // sample, should write a real program.

statements.py

@@ -30,7 +30,7 @@ def __init__(self):
 
 	def print(self, stmt):
 		# Visitor.start_walk
-		print(stmt.accept(visitor=self))
+		print(f'{stmt.__class__.__name__}({stmt.accept(visitor=self)})')
 
 	def _exprVisit(self, expr):
 		return expr.accept(visitor=self.exprPrinter)