++++++++++++
-(t is used for types, T is the context, and + is used for in)
+(v is used for values, e for expressions, s for statements, c is the context)
-[Eq, NEq]
+[Eq, NEq, Plus, Minus, Times, Div, Lt, ELt, Gt, EGt]
-T+ e1 Eq e2:bool <= T+ e1:t & T+ e2:t
-
-If e1 and e2 are of the same type, then Eq or NEq return bool
-
-
-[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
-
-
-[Lt, ELt, Gt, EGt]
-
-T+ e1 Lt e2:bool <= T+ e1:int & T+ e2:int
-
-The operators Lt/ELt/Gt/EGt return bool if both operands are ints
+<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]
-T+ i := e:t <= i:t in T & T+ e:t
-
-The assignemnt of e to i returns type t if both i and e have type t.
+<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]
-T+ ENeg e:int <= T+ e:int
+<e,c> => <-v,c'> <= <e,c> => <v,c'>
-ENeg e returns int if e is of type int
[ENot]
-T+ ENot e:bool <= e:bool
-
-ENot e returns bool if e is of type bool
+<e,c> => <not v,c'> <= <e,c> => <v,c'>
[EVar]
-T+ i:t <= i:t in T
-
-i has type t if i is defined in the context with type t.
+<i,c> => <c(i),c>
[EInt]
-T+ n:int
-
-n has type int
+<n,c> => <n,c>
[EBool]
-T+ b:bool
-
-b has type bool
-
-[EReadI]
-
-T+ n:int
+<b,c> => <b,c>
-EReadI returns an int
+[EReadI,EReadB]
-[EReadB]
-
-T+ b:bool
-
-EReadB returns a bool
+<c> => <v,c'> <= <IO,c> => <v,c'>
[EPost]
-T+ EPost i:int <= i:int in T
+<i,c> => <v,c[i->v']> <= c(i) => v, v±1 => v'
-EPost i is of type int if i is defined in T with type int.
+Look up the variable, add/subtract 1 from the value then return the old value and context with modified value
[SExp]
-T+ e <= T+ e:t
+<e,c> => c' <= <e,c> => <v,c'>
[SBlock]
-T+ s;SBlock ss <= T+ s => T' , T'+ ss => T''
+<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
-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'
+[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 is of type bool and s1 and and s2 typechecks in the context T, then the same context is returned
+<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
-
-If e is of type bool and s typechecks in context T then the same context is returned
+<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+ t i = e => T,i:t <= i not in T & e:t
+<i := e,c> => c'[i->v] <= <e,c> => <v,c'>
-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.
+Adds i with value v to the current scope in the context
[SDeclD]
-T+ t i => T,i:t <= i not in T
+<int i,c> => c[i->0]
+<bool i,c> => c[i->false]
-if i is not declared in the current scope, then i is added to the context with type t
+Adds i with default value in the current scope
[SNoop]
-T+ s
+<SNoop,c> => c
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
+<e,c> => c'' <= <e,c> => <v,c'> <IO v,c'> => c''
projects / proglang.git / blobdiff