¡Ya hay funciones y (algunas) expresiones!

4 files changed, 281 insertions, 16 deletions

diff --git a/compilador/astree/expr.py b/compilador/astree/expr.py
index 1bb7f4f..d5a2cb0 100644
--- a/compilador/astree/expr.py
+++ b/compilador/astree/expr.py
@@ -3,10 +3,19 @@ from enum import Enum, auto
 from typing import List, Optional
 
 from astree.type import Type
+from astree.ident import Ident
 
 Expr = None
 
-# An assignment expression
+# An identifier access expression.
+#
+#     a
+AccessIdentifier = Ident
+
+# An access expression.
+AccessExpr = AccessIdentifier
+
+# An assignment expression.
 #
 #     a = 10
 @dataclass
@@ -14,7 +23,7 @@ class AssignExpr:
     _object: Expr
     value: Expr
 
-# A binary arithmetic operator
+# A binary arithmetic operator.
 class BinarithmOp(Enum):
     BAND = '&'
     BOR = '|'
@@ -92,19 +101,23 @@ class IfExpr:
 # A print statement.
 #
 #     imprimir a
-PrintExpr = Expr
+@dataclass
+class PrintExpr:
+    expr: Expr
 
 # A read statement.
 #
 #     leer a
-ReadExpr = Expr
+@dataclass
+class ReadExpr:
+    expr: AccessExpr
 
 # A return statement.
 #
 #     return a
 ReturnExpr = Optional[Expr]
 
-# A Javañol expression
-Expr = (AssignExpr | BinarithmExpr | CallExpr | ConstantExpr |
-        ForExpr | IfExpr | CompoundExpr | PrintExpr |
-        ReadExpr | ReturnExpr)
+# A Javañol expression.
+Expr = (AccessExpr | AssignExpr | BinarithmExpr | CallExpr |
+        ConstantExpr | ForExpr | IfExpr | CompoundExpr |
+        PrintExpr | ReadExpr | ReturnExpr)
diff --git a/compilador/errors.py b/compilador/errors.py
index 5a4e7a2..6bb05b8 100644
--- a/compilador/errors.py
+++ b/compilador/errors.py
@@ -15,8 +15,11 @@ class Error:
         'S_ESPERA_PC': 'Se esperaba `;`',
     }
 
-    def __init__(self, msg: str = None):
-        self.message = msg
+    def __init__(self, msg: str = None, numlinea: int = None):
+        if numlinea:
+            self.message = "Error en la línea %d: %s" % (numlinea, msg)
+        else:
+            self.message = msg
 
     @classmethod
     def lex(self, error, numlinea: int):
diff --git a/compilador/parse/decl.py b/compilador/parse/decl.py
index 93666fc..aa9e23a 100644
--- a/compilador/parse/decl.py
+++ b/compilador/parse/decl.py
@@ -58,9 +58,13 @@ class ParseDecl:
         if type(proto) is Error:
             return proto
 
+        init = ParseExpr(self.parser).compound_expr()
+        if type(init) is Error:
+            return init
+
         return DeclFunc(ident = ident,
                         prototype = proto,
-                        body = None)
+                        body = init)
 
     # Parses a declaration.
     def decl(self) -> (Decl | Error):
diff --git a/compilador/parse/expr.py b/compilador/parse/expr.py
index 23b1a61..492b4e6 100644
--- a/compilador/parse/expr.py
+++ b/compilador/parse/expr.py
@@ -1,12 +1,257 @@
+from typing import NoReturn, Optional, cast
+
+from tabla import Token, LexToken
 from parse.base import BaseParser
+from parse.ident import ParseIdent
 from errors import Error
-from astree.expr import Expr
+from astree.expr import Expr, BinarithmOp, ConstantExpr, NumberConstant, CallExpr, PrintExpr, BinarithmExpr, CompoundExpr, ReadExpr, AccessExpr, AssignExpr
 
 class ParseExpr:
     def __init__(self, parser: BaseParser):
         self.parser = parser
 
-    def expr(self) -> Expr | Error:
-        self.parser.iterador.next()
-        return
-    
+    def expr(self) -> (Expr | Error):
+        obj = self.binarithm(None, 0)
+
+        # =
+        tok = self.parser._try(Token.EQUAL)
+        if not tok:
+            return obj
+
+        error = self.parser.synassert(
+            isinstance(obj, AccessExpr),
+            "Se esperaba un objeto como destino de la asignación.")
+        if type(error) is Error:
+            return error
+
+        # Expresión
+        expr = self.expr()
+        if type(expr) is Error:
+            return expr
+
+        return AssignExpr(_object = obj,
+                          value = expr)
+        
+    # WIP
+    def binarithm(self, lvalue: Expr, i: int) -> (Expr | Error):
+        print(f'binarithm({lvalue}, {i})')
+        _lvalue = lvalue
+        if not lvalue:
+            _lvalue = self.cast(lvalue)
+            if type(_lvalue) is Error:
+                return _lvalue
+        print(f'lvalue = {_lvalue}')
+        
+        tok = self.parser.lex()
+        print(f'tok = {tok}')
+        j: int = self.precedence(tok.tipo)
+        while j >= i:
+            op = self.binop_for_tok(tok.tipo)
+
+            rvalue = self.cast(_lvalue)
+            if type(rvalue) is Error:
+                return rvalue
+
+            tok = self.parser.lex()
+            k: int = self.precedence(tok.tipo)
+            while k > j:
+                self.parser.unlex()
+                rvalue = self.binarithm(rvalue, k)
+                if type(rvalue) is Error:
+                    return rvalue
+                tok = self.parser.lex()
+                
+                k = self.precedence(tok.tipo)
+
+            _lvalue = BinarithmExpr(op = op,
+                                    lvalue = _lvalue,
+                                    rvalue = rvalue)
+            
+            j = self.precedence(tok.tipo)
+
+        self.parser.unlex()
+        return _lvalue
+
+    def call(self, lvalue: Expr) -> (Expr | Error):
+        args: List[Expr] = []
+
+        while not self.parser._try(Token.R_PAREN):
+            # Expresión
+            expr = self.expr()
+            if type(expr) is Error:
+                return epr
+
+            args.append(expr)
+
+            # ,
+            if self.parser._try(Token.COMMA):
+                continue
+
+            # )
+            if self.parser._try(Token.R_PAREN):
+                break
+
+        return CallExpr(lvalue = lvalue,
+                        args = args)
+
+    def compound_expr(self) -> (Expr | Error):
+        items: List[Expr] = []
+
+        # {
+        lbracket = self.parser.want(Token.L_BRACKET)
+        if type(lbracket) is Error:
+            return lbracket
+
+        while True:
+            # }
+            item = self.parser.peek(Token.R_BRACKET)
+            if item: break
+            
+            item = self.expr()
+            if type(item) is Error:
+                return item
+            
+            items.append(item)
+
+            # ;
+            semicolon = self.parser.want(Token.SEMICOLON)
+            if type(semicolon) is Error:
+                return semicolon
+
+        # }
+        rbracket = self.parser.want(Token.R_BRACKET)
+        if type(rbracket) is Error:
+            return rbracket
+
+        return CompoundExpr(exprs = items)
+
+    def builtin(self) -> (Expr | Error):
+        tok: LexToken = self.parser.peek(Token.PRINT, Token.READ)
+        if not tok:
+            return self.postfix(None)
+
+        if tok.tipo == Token.PRINT:
+            return self.print_expr()
+        elif tok.tipo == Token.READ:
+            return self.read_expr()
+            
+        
+    def postfix(self, lvalue: Optional[Expr]) -> (Expr | Error):
+        _lvalue: Optional[Expr] = lvalue
+        if not lvalue:
+            _lvalue = self.plain_expression()
+            if type(_lvalue) == Error:
+                return _lvalue
+
+        tok: LexToken = self.parser._try(Token.L_PAREN)
+        if not tok:
+            return _lvalue
+
+        _next: Optional[LexToken] = None
+        if tok == Token.L_PAREN:
+            return self.call(_lvalue)
+
+        return self.postfix(_next)
+
+    def print_expr(self) -> (Expr | Error):
+        _print = self.parser.want(Token.PRINT)
+        if type(_print) is Error:
+            return _print
+
+        lparen = self.parser.want(Token.L_PAREN)
+        if type(lparen) is Error:
+            return lparen
+
+        expr = self.expr()
+        if type(expr) is Error:
+            return expr
+
+        rparen = self.parser.want(Token.R_PAREN)
+        if type(rparen) is Error:
+            return rparen
+
+        return PrintExpr(expr = expr)
+
+    def read_expr(self) -> (Expr | Error):
+        _read = self.parser.want(Token.READ)
+        if type(_read) is Error:
+            return _read
+
+        ident = ParseIdent(self.parser).ident()
+        if type(ident) is Error:
+            return ident
+        
+        return ReadExpr(expr = ident)
+
+    # WIP
+    def cast(self, lvalue: Optional[Expr]) -> (Expr | Error):
+        return self.unarithm()
+
+    # WIP
+    def constant(self) -> (Expr | Error):
+        tok: LexToken = self.parser.lex()
+        expr: Optional[ConstantExpr] = None
+        if tok.tipo == Token.STRING_LIT:
+            expr: str = tok.valor
+        elif tok.tipo == Token.INT_LIT:
+            expr = NumberConstant(value = tok.valor)
+        elif tok.tipo == Token.BOOLEAN_LIT:
+            expr: bool = tok.valor
+        else:
+            return Error(msg = "Se esperaba una constante.", numlinea = tok.numlinea)
+        return expr
+
+    # WIP
+    def plain_expression(self) -> (Expr | Error):
+        tok: LexToken = self.parser.peek()
+        if tok.tipo in [Token.BOOLEAN_LIT, Token.CHAR_LIT, Token.INT_LIT, Token.STRING_LIT]:
+            return self.constant()
+        elif tok.tipo == Token.L_PAREN:
+            lparen = self.parser.want(Token.L_PAREN)
+            if type(lparen) is Error:
+                return lparen
+            expr = self.expr()
+            if type(expr) is Error:
+                return expr
+            rparen = self.parser.want(Token.R_PAREN)
+            if type(rparen) is Error:
+                return rparen
+        elif tok.tipo == Token.IDENT:
+            ident = ParseIdent(self.parser).ident()
+            if type(ident) is Error:
+                return ident
+            return ident
+
+    def unarithm(self) -> (Expr | Error):
+        return self.builtin()
+
+    def binop_for_tok(self, tok: Token) -> (BinarithmOp | NoReturn):
+        if tok is Token.SLASH:
+            return BinarithmOp.DIV
+        elif tok is Token.GT:
+            return BinarithmOp.GT
+        elif tok is Token.GEQ:
+            return BinarithmOp.GTEQ
+        elif tok is Token.EQEQ:
+            return BinarithmOp.LEQUAL
+        elif tok is Token.LT:
+            return BinarithmOp.LESS
+        elif tok is Token.LEQ:
+            return BinarithmOp.LESSEQ
+        elif tok is Token.MINUS:
+            return BinarithmOp.MINUS
+        elif tok is Token.NOTEQ:
+            return BinarithmOp.NEQUAL
+        elif tok is Token.PLUS:
+            return BinarithmOp.PLUS
+        elif tok is Token.TIMES:
+            return BinarithmOp.TIMES
+
+    def precedence(self, tok: Token) -> int:
+        if tok in [Token.EQEQ, Token.NOTEQ]:
+            return 0
+        elif tok in [Token.PLUS, Token.MINUS]:
+            return 1
+        elif tok in [Token.TIMES, Token.SLASH]:
+            return 2
+        return -1