updating documentation

[proglang.git] / documentation

diff --git a/documentation b/documentation
index 28be8953c583ac46e7fc73b3998982312167a67d..47008eefba987fb88613cf46094072b64c289764 100644 (file)
--- a/documentation
+++ b/documentation
@@ -1,18 +1,121 @@
 ####### 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.
+
+
+semantic rules
+++++++++++++
+
+
+(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]
+
+<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
+
+
+[Assignment]
+
+<i := e,c> => c'[i -> v] <= <e,c> => <v,c'>
+
+Assign the value v to i in the first scope i is found in.
+
+[ENeg]
+
+<e,c> => <-v,c'> <= <e,c> => <v,c'>
+
+
+[ENot]
+
+<e,c> => <not v,c'> <= <e,c> => <v,c'>
+
+[EVar]
+
+<i,c> => <c(i),c>
+
+[EInt]
+
+<n,c> => <n,c>
+
+[EBool]
+
+<b,c> => <b,c>
+
+[EReadI,EReadB]
+
+<c> => <v,c'> <= <IO,c> => <v,c'>
+
+[EPost]
+
+<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]
+
+<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]
+
+<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]
+
+<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]
+
+<i := e,c> => c'[i->v] <= <e,c> => <v,c'>
+
+Adds i with value v to the current scope in the context
+
+[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''