Call-by-Name The evaluation of actuals is delayed until their use in callee Can be thought of as in-line expansion (but isn't!) Can be implemented by using parameterless evaluation procedures (sometimes called thunks)that are created for each actual: int thunk 1()( return 1 2; } void foo(int a,int b){ int thunk 2()( …a…b… return 3; } } void foo(proc f,proc g){ fo0(1+2,3); …p()…q()… foo(thunk 1,thunk 2); CS308 Compiler Theory 6Call-by-Name • The evaluation of actuals is delayed until their use in callee • Can be thought of as in-line expansion (but isn’t!) • Can be implemented by using parameterless evaluation procedures (sometimes called thunks) that are created for each actual: int thunk_1() { return 1 + 2; } void foo(int a, int b) { … a … b … } int thunk_2() { return 3; } … foo(1+2, 3); void foo(proc f, proc g) { … p() … q() … } … … foo(thunk_1, thunk_2); … 6 CS308 Compiler Theory