Language "IMP"

#4 Programs and variable declarations

Syntax
  Pgm : pgm ::= 'int' idlist ';' stmt

Semantics
  run[[ _:pgm ]] : =>null-type

Rule

  run[[ 'int' IL ';' Stmt ]] = 
	scope( collateral(declare-int-vars[[ IL ]]), 
	       execute[[ Stmt ]] )

Syntax
  IL : idlist ::= id (',' idlist)?

Semantics
  declare-int-vars[[ _: idlist ]] : (=>environments)+

Rule

  declare-int-vars[[ I ]] =
    bind(id[[ I ]], allocate-initialised-variable(integers, 0))
Rule
  declare-int-vars[[ I ',' IL ]] = 
  	declare-int-vars[[ I ]], declare-int-vars[[ IL ]]