X-Git-Url: https://ruin.nu/git/?p=proglang.git;a=blobdiff_plain;f=documentation;h=bbb604f08eb7bb7225e8219460a812238e158726;hp=70bd0c818b7f8c298ca3658a67729c6413db122b;hb=d553df8dfdffca78342d6fae142ceded9cd64415;hpb=ef4659dbfa5051372cf067f8c0ed2bbe77146650

diff --git a/documentation b/documentation
index 70bd0c8..bbb604f 100644
--- a/documentation
+++ b/documentation
@@ -1,97 +1,143 @@
 ####### 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
+Files:
+Typechecker.hs: Simple modification of the bnfc-generated Testsyntax which calls the type-checking functions.
 
+Typecheck.hs: Contains the type-checking functions typeCheckExp, typeCheckVar and typeCheckStm and some utility functions, responsible for the entire type-checking process.
 
-data types:
-integers and booleans.
+Abssyntax.hs, Parsyntax.y, Lexsyntax.x,ErrM.hs,Printsyntax.hs,Skelsyntax.hs: The files generated by bnfc, only modification is the removal of the Bool type in Abssyntx.hs so haskell's internal type can be used.
 
-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)
+typing rules
+++++++++++++
 
-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.
+(t is used for types, T is the context, and + is used for in)
 
 
+[Eq, NEq]
 
+T+ e1 Eq e2:bool  <=  T+ e1:t  &  T+ e2:t
 
-typing rules
-++++++++++++
+If e1 and e2 are of the same type, then Eq or NEq return bool
 
 
-(t is little tau, T is large tau, E is 'in', and + is that other symbol)
+[Plus, Minus, Times, Div]
 
+T+ e1 Plus e2:int  <=  T+ e1:int  &  T+ e2:int
 
+The operators Plus/Minus/Times/Div return int if both operands are ints
 
-[Eq, Neq]
 
-e:bool  <=  e1:t  &  e2:t
-where e is e1 Eq e2.
+[Lt, ELt, Gt, EGt]
 
+T+ e1 Lt e2:bool  <=  T+ e1:int  &  T+ e2:int
 
-[Plus, Minus, Times, Div]
+The operators Lt/ELt/Gt/EGt return bool if both operands are ints
 
-e:int  <=  e1:int  &  e2:int
-where e is e1 Plus e2.
 
+[Assignment]
 
-[Lt, ELt, Gt, EGt]
+T+ i := e:t  <=  i:t in T  &  T+ e:t
 
-e:bool  <=  e1:int  &  e2:int
-where e is e1 Lt e2.
+The assignemnt of e to i returns type t if both i and e have type t.
 
 
-[Assignment]
+[ENeg]
 
-T+ i := e:t  <=  i:t E T  &  T+ e:t
-where the assignment is identifier i = expression e.
+T+ ENeg e:int  <=  T+ e:int
 
+ENeg e returns int if e is of type int
 
-[ExpT]
+[ENot]
 
-u,e:t  <=  e:t  &  u:t
-where the expression is type u expression e.
+T+ ENot e:bool  <=  e:bool
 
+ENot e returns bool if e is of type bool
 
-[ENeg]
+[EVar]
 
-e:int  <=  e:int
+T+ i:t <= i:t in T
 
+i has type t if i is defined in the context with type t.
 
-[ENot]
+[EInt]
+
+T+ n:int
+
+n has type int
+
+[EBool]
 
-e:bool  <=  e:bool
+T+ b:bool
 
+b has type bool
 
-[SExp, SBlock]
+[EReadI]
 
-S:NoType  <=  e:t
+T+ n:int
+
+EReadI returns an int
+
+[EReadB]
+
+T+ b:bool
+
+EReadB returns a bool
+
+[EPost]
+
+T+ EPost i:int <= i:int in T
+
+EPost i is of type int if i is defined in T with type int.
+
+[SExp]
+
+T+ e   <=  T+ e:t
+
+[SBlock]
+
+T+ s;SBlock ss <= T+ s => T' , T'+ ss => T''
+
+the first statment s, in the block, is typechecked in the context T and returns the context T', the rest of the block is then recursively typeckecked in the context T' 
 
 
 [SIf]
 
 T+ if e then s1 else s2  <=  T+ e:bool  &  T+ s1  &  T+ s2
 
+if e is of type bool and s1 and and s2 typechecks in the context T, then the same context is returned
+
 
 [SWhile]
 
 T+ while e do s  <=  T+ e:bool  &  T+ s
 
+If e is of type bool and s typechecks in context T then the same context is returned
+
+
 
 [SDecl]
 
-T+ i:t => T', i:t  <=  i!ET  &  e:t  &  u:t
+T+ t i = e => T,i:t  <=  i not in T  &  e:t 
+
+if i and e are of the same type and i is not declared in the current scope then i is added with type t to the context.
+
+[SDeclD]
 
-(Type u Ident i = Exp e)
+T+ t i => T,i:t  <=  i not in T
 
+if i is not declared in the current scope, then i is added to the context with type t
 
+[SNoop]
 
+T+ s
 
+SNoops does nothing so the same context is returned
 
+[SPrint]
 
+T+ e <= T+ e:t
 
+if e has type t then SPrint returns the same context