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6, 9: PROGRAMMER INTERFACE 
If the system designer has decided to opt for the sort of 
user interface that I have been describing» and if he 
decides to use a data dictionary approach such as is 
appropriate, then large parts of the programmer interface 
fall out as a by-product. 
The programmer of individual modules NEVER needs to consider 
uhere, how and when he will prompt the analyst for control 
input. He doesn‘t have to compose messages and prompts. He 
doesn't have to loop back and reprompt if the analyst has 
typed an error. He doesn’t have to clear the screen and 
write pretty menus. 
In short, he can discard what tupicallu turns out to be 
about 50% of his code, and simply sau "GIVE-ME-PARAMETERS" 
to the control parameter dictionary. He may have to confirm 
that some of these parameters have reasonable values, 
because he will probably not want to confuse the interface 
with too much conditional value checking. (This keeps the 
interface application independent.) 
All errors detected at this level will necessarily become 
fatal, but the interface is there to catch uour analyst 
anyway. 
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