X-Git-Url: https://ruin.nu/git/?a=blobdiff_plain;f=documentation;h=269e93139c744f83508a076206088f76e7634b81;hb=2316d61f350f8b39c9a3f76b91d1d14796d5183b;hp=28be8953c583ac46e7fc73b3998982312167a67d;hpb=9597d94cbb1b328c27883c8421b1fef3211fb698;p=proglang.git diff --git a/documentation b/documentation index 28be895..269e931 100644 --- a/documentation +++ b/documentation @@ -1,18 +1,86 @@ ####### 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. + +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. + + +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] + +S:NoType <= e:t + + +[SIf] + +T+ if e then s1 else s2 <= T+ e:bool & T+ s1 & T+ s2 + + +[SWhile] + +T+ while e do s <= T+ e:bool & T+ s + + +[SDecl] + +T+ i:t => T', i:t <= i!ET & e:t & u:t + +(Type u Ident i = Exp e) + -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.