####### DOCUMENTATIATOIAITAT ION ########
+Usage:
-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
+./CompInt [-c] [file]
+-c : Compile [file], interprets if it isn't specified
-data types:
-integers and booleans.
+if no arguments are specified then the file is interpreted
-comments:
-// and /* */ comments are allowed.
+Files:
+Interpret.hs: Handles the interpretation of a program
-(For compilation to work the Bool type in Abssyntax has to be removed so the internal haskell type is used)
+Compile.hs: Compiles the program into a c program
-shift/reduce conflicts:
+Typechecker.hs: Simple modification of the bnfc-generated Testsyntax which calls the type-checking functions.
-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.
+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
+semantic rules
++++++++++++
-(t is little tau, T is large tau, E is 'in', and + is that other symbol)
+(v is used for values, e for expressions, s for statements, c is the context)
+[Eq, NEq, Plus, Minus, Times, Div, Lt, ELt, Gt, EGt]
-[Eq, Neq]
+<e1 o e2,c> => <v,c''> <= <e1,c> => <v1,c'> <e2,c'> => <v2,c''> v is the result of using operator o on v1 and v2
-e:bool <= e1:t & e2:t
-where e is e1 Eq e2.
+[Assignment]
-[Plus, Minus, Times, Div]
+<i := e,c> => c'[i -> v] <= <e,c> => <v,c'>
-e:int <= e1:int & e2:int
-where e is e1 Plus e2.
+Assign the value v to i in the first scope i is found in.
+[ENeg]
-[Lt, ELt, Gt, EGt]
+<e,c> => <-v,c'> <= <e,c> => <v,c'>
-e:bool <= e1:int & e2:int
-where e is e1 Lt e2.
+[ENot]
-[Assignment]
+<e,c> => <not v,c'> <= <e,c> => <v,c'>
-T+ i := e:t <= i:t E T & T+ e:t
-where the assignment is identifier i = expression e.
+[EVar]
+<i,c> => <c(i),c>
-[ExpT]
+[EInt]
-u,e:t <= e:t & u:t
-where the expression is type u expression e.
+<n,c> => <n,c>
+[EBool]
-[ENeg]
+<b,c> => <b,c>
-e:int <= e:int
+[EReadI,EReadB]
+<c> => <v,c'> <= <IO,c> => <v,c'>
-[ENot]
+[EPost]
-e:bool <= e:bool
+<i,c> => <v,c[i->v']> <= c(i) => v, v±1 => v'
+Look up the variable, add/subtract 1 from the value then return the old value and context with modified value
-[SExp, SBlock]
+[SExp]
-S:NoType <= e:t
+<e,c> => c' <= <e,c> => <v,c'>
+[SBlock]
+
+<SBlock s,c> => c''' <= push(c) => c' <s,c'> => c'' pop(c'') => c'''
+
+Push a new scope onto the context, execute the statements in this context and the pop the scope from the context
+
+[SEQ]
+
+<s1;s2,c> => c'' <= <s1,c> => c' <s2,c'> => c''
[SIf]
-T+ if e then s1 else s2 <= T+ e:bool & T+ s1 & T+ s2
+<if e s1 s2,c> => pop(c''') <= <e,c> => <true,c'> push(c') <s1,c''> => c'''
+
+<if e s1 s2,c> => pop(c''') <= <e,c> => <false,c'> push(c') <s2,c''> => c'''
[SWhile]
-T+ while e do s <= T+ e:bool & T+ s
+<while e s,c> => c' => <e,c> => <false,c'>
+
+<while e s,c> => pop(c''') => <e,c> => <true,c'> push(c') => c'' <s,c''> => c'''
[SDecl]
-T+ i:t => T', i:t <= i!ET & e:t & u:t
+<i := e,c> => c'[i->v] <= <e,c> => <v,c'>
+
+Adds i with value v to the current scope in the context
-(Type u Ident i = Exp e)
+[SDeclD]
+<int i,c> => c[i->0]
+<bool i,c> => c[i->false]
+Adds i with default value in the current scope
+[SNoop]
+<SNoop,c> => c
+SNoops does nothing so the same context is returned
+[SPrint]
+<e,c> => c'' <= <e,c> => <v,c'> <IO v,c'> => c''
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