check

Author: jsiek

tests/var/add.golden

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+42

tests/var/add.in

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+

tests/var/add.py

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+print(40 + 2)

tests/var/input.golden

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+42

tests/var/input.in

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+42

tests/var/input.py

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+print(input_int())

tests/var/zero.golden

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+0

tests/var/zero.in

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+

tests/var/zero.py

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+print(0)

type_check_Pvar.py

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+from ast import *
+
+def check_type_equal(t1, t2, e):
+  if t1 != t2:
+    raise Exception('error: ' + repr(t1) + ' != ' + repr(t2) + ' in ' + repr(e))
+
+class TypeCheckPvar:
+          
+  def type_check_exp(self, e, env):
+    match e:
+      case BinOp(left, Add(), right):
+        l = self.type_check_exp(left, env)
+        check_type_equal(l, int, left)
+        r = self.type_check_exp(right, env)
+        check_type_equal(r, int, right)
+        return int
+      case UnaryOp(USub(), v):
+        t = self.type_check_exp(v, env)
+        check_type_equal(t, int, v)
+        return int
+      case Name(id):
+        return env[id]
+      case Constant(value) if isinstance(value, int):
+        return int
+      case Call(Name('input_int'), []):
+        return int
+      case _:
+        raise Exception('error in TypeCheckPvar.type_check_exp, unhandled ' + repr(e))
+
+  def type_check_stmts(self, ss, env):
+    if len(ss) == 0:
+      return
+    match ss[0]:
+      case Assign([lhs], value):
+        t = self.type_check_exp(value, env)
+        if lhs.id in env:
+          check_type_equal(env[lhs.id], t, value)
+        else:
+          env[lhs.id] = t
+        return self.type_check_stmts(ss[1:], env)
+      case Expr(Call(Name('print'), [arg])):
+        t = self.type_check_exp(arg, env)
+        check_type_equal(t, int, arg)
+        return self.type_check_stmts(ss[1:], env)
+      case Expr(value):
+        self.type_check_exp(value, env)
+        return self.type_check_stmts(ss[1:], env)
+      case _:
+        raise Exception('error in TypeCheckPvar.type_check_stmt, unhandled ' + repr(s))
+
+  def type_check_P(self, p):
+    match p:
+      case Module(body):
+        self.type_check_stmts(body, {})