SL-4-Definitions

Language "SL"

#4 Function definitions

Syntax
  FunDef : fun-def ::= 'function' id '(' id-list^? ')' block   

Semantics
  declare[[ FunDef*:fun-def* ]] : => environments

Rule

  declare[[ 'function' Id '(' IdList^? ')' Block ]] =
    { id[[Id]] |->
      function closure
        scope(initialise-local-variables,
          sequential(
            pass-list[[IdList^?]],
            handle-return(exec[[Block]]))) }
Rule
  declare[[ ]] = map( )
Rule
  declare[[ FunDef FunDef⁺ ]] = 
    collateral(declare[[FunDef]], declare[[FunDef⁺]])

## Parameter lists


Syntax
  IdList : id-list ::= id (',' id-list)^?

Semantics
  pass-list[[ IdList:id-list^? ]] : lists(values) => null-type

Rule

  pass-list[[ ]] = null-value
Rule
  pass-list[[ Id ]] =
    local-variable-initialise(id[[Id]], checked head given)
Rule
  pass-list[[ Id ',' IdList ]] = 
    sequential(
      local-variable-initialise(id[[Id]], checked head given), 
      give(checked tail given, pass-list[[IdList]]))