Go backward to The Correspondence PrincipleGo up to TopGo forward to Consequences of Correspondence |

- Semantics of identifiers:
- Independent of way in which identifier is bound.
- Understanding more easy.

- Direction for language extension:
- Existing abstraction (e.g. procedures).
- Introduce parameter form (e.g. command parameter).

- Correspondence may fail:
- Evaluate functions lazily but expression parameters eagerly.
**var**`A`:**newint**;**fun**`F`= @`A`+1**proc**`P`(`X`:`intexp`) =`A`:=`X`+`F`;`A`:=`X`+`F`- Both
`X`and`F`have type`intexp`. `X`and`F`are evaluated differently.- Syntactic distinction:
`A`:=`X`+(**eval**`F`)

Author: Wolfgang Schreiner

Last Modification: May 7, 1998