X-Git-Url: https://ruin.nu/git/?a=blobdiff_plain;f=documentation;h=c3ac4e08ba815c574432d3e2f0905cf120a460e1;hb=9625a8a7eb7aebeb161ca15cf66cff5699f89103;hp=70bd0c818b7f8c298ca3658a67729c6413db122b;hpb=ef4659dbfa5051372cf067f8c0ed2bbe77146650;p=proglang.git

diff --git a/documentation b/documentation
index 70bd0c8..c3ac4e0 100644
--- a/documentation
+++ b/documentation
@@ -1,97 +1,110 @@
 ####### 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)
-
-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
+++++++++++++
 
 
+(v is used for values, e for expressions, s for statements, c is the context)
 
 
-typing rules
-++++++++++++
+[Eq, NEq, Plus, Minus, Times, Div, Lt, ELt, Gt, EGt]
 
+<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
 
-(t is little tau, T is large tau, E is 'in', and + is that other symbol)
 
+[Assignment]
 
+<i := e,c> => c'[i -> v] <= <e,c> => <v,c'>
 
-[Eq, Neq]
+Assign the value v to i in the first scope i is found in.
 
-e:bool  <=  e1:t  &  e2:t
-where e is e1 Eq e2.
+[ENeg]
 
+<e,c> => <-v,c'> <= <e,c> => <v,c'>
 
-[Plus, Minus, Times, Div]
 
-e:int  <=  e1:int  &  e2:int
-where e is e1 Plus e2.
+[ENot]
 
+<e,c> => <not v,c'> <= <e,c> => <v,c'>
 
-[Lt, ELt, Gt, EGt]
+[EVar]
 
-e:bool  <=  e1:int  &  e2:int
-where e is e1 Lt e2.
+<i,c> => <c(i),c>
 
+[EInt]
 
-[Assignment]
+<n,c> => <n,c>
 
-T+ i := e:t  <=  i:t E T  &  T+ e:t
-where the assignment is identifier i = expression e.
+[EBool]
 
+<b,c> => <b,c>
 
-[ExpT]
+[EReadI,EReadB]
 
-u,e:t  <=  e:t  &  u:t
-where the expression is type u expression e.
+<c> => <v,c'> <= <IO,c> => <v,c'>
 
+[EPost]
 
-[ENeg]
+<i,c> => <v,c[i->v']> <= c(i) => v, v±1 => v'
 
-e:int  <=  e:int
+Look up the variable, add/subtract 1 from the value then return the old value and context with modified value
 
+[SExp]
 
-[ENot]
+<e,c> => c' <= <e,c> => <v,c'>
 
-e:bool  <=  e:bool
+[SBlock]
 
+<SBlock s,c> => c'''  <= push(c) => c' <s,c'> => c'' pop(c'') => c'''
 
-[SExp, SBlock]
+Push a new scope onto the context, execute the statements in this context and the pop the scope from the context
 
-S:NoType  <=  e:t
+[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''