typing rules in documentation

[proglang.git] / documentation

diff --git a/documentation b/documentation
index cb693df417c88f4430589c5ac0de2ce533360c91..70bd0c818b7f8c298ca3658a67729c6413db122b 100644 (file)
--- a/documentation
+++ b/documentation
@@ -1,77 +1,97 @@
 ####### DOCUMENTATIATOIAITAT ION ########
 
 
+a simple c-like language with support for if/else-statements, while-loops and the standard arithmetic (+, -, /, *) and comparison expressions (<, >, <=, >=, ==, !=). also, post increase/decrease expressions (++, --) are supported. Assignments are allowed in expressions, but they are only allowed on the right side of arithmetic/comparision operators if they are put inside parenthesis
 
 
-a simple c-like language with support for if/else-statements, while-loops and the standard arithmetic (+, -, /, *) and comparison expressions (<, >, <=, >=, ==, !=). also, increase/decrease expressions (++, --) are supported.
-
 data types:
 integers and booleans.
 
 comments:
 // and /* */ comments are allowed.
 
+(For compilation to work the Bool type in Abssyntax has to be removed so the internal haskell type is used)
+
+shift/reduce conflicts:
+
+if with else: 1 conflict
+An if statement before the else could be reduced to an if statement lacking the else, but the correct thing is to shift it onto the stack.
+
+
+
+
+typing rules
+++++++++++++
+
+
+(t is little tau, T is large tau, E is 'in', and + is that other symbol)
+
+
+
+[Eq, Neq]
+
+e:bool  <=  e1:t  &  e2:t
+where e is e1 Eq e2.
+
+
+[Plus, Minus, Times, Div]
+
+e:int  <=  e1:int  &  e2:int
+where e is e1 Plus e2.
+
+
+[Lt, ELt, Gt, EGt]
+
+e:bool  <=  e1:int  &  e2:int
+where e is e1 Lt e2.
+
+
+[Assignment]
+
+T+ i := e:t  <=  i:t E T  &  T+ e:t
+where the assignment is identifier i = expression e.
 
 
+[ExpT]
 
+u,e:t  <=  e:t  &  u:t
+where the expression is type u expression e.
 
 
+[ENeg]
 
+e:int  <=  e:int
 
 
+[ENot]
 
+e:bool  <=  e:bool
 
 
+[SExp, SBlock]
 
-examples:
+S:NoType  <=  e:t
 
-fib
----
-int n1 = 0;
-int n2 = 1;
-int n = readInt;
 
-while(n-- > 0){
-  int temp = n1+n2;
-  n1 = n2;
-  n2 = temp;
-}
-print n2;
+[SIf]
 
+T+ if e then s1 else s2  <=  T+ e:bool  &  T+ s1  &  T+ s2
 
-tests while, decr and assignment.
 
+[SWhile]
 
+T+ while e do s  <=  T+ e:bool  &  T+ s
 
-if
---
-if (readBool) {
-  if (readInt < 0)
-    print true;
-  else
-    print false;
-}
 
+[SDecl]
 
-tests if and if/else.
+T+ i:t => T', i:t  <=  i!ET  &  e:t  &  u:t
 
+(Type u Ident i = Exp e)
 
 
-sum
----
-int n;
-int sum = 0;
-while ((n = readInt) != -1) sum = sum + n;
-print sum;
 
 
 
 
-var
----
-int a = 3;
-int b = a - 5;
-int c = a + b*7;
-bool d = a == b;
 
-tests simple variable operations.
\ No newline at end of file