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Ki-Wing Ho and Eric Fox
Computer Science 429b
Professor Hudak
Final Project: User Manual
Control Commands:
(DO <clause> WHILE <cond>)
Loop, executing a list of commands, then checking a condition and
looping again if the condition is true.
(REPEAT n TIMES)
WHILE cn cl
IF cn THEN cl1 [ELSE cl2]
Load a file:
USE "filename
Environment Commands:
MAKE "nm v
LOCAL "nm
TO :nm1 :nm2 :nm3 ... cl
Text I/O:
PRINT v
READ
Graphics Commands:
FORWARD n
BACKWARD n
SETXY n1 n2
LEFT n
RIGHT n
PENUP
PENDOWN
HIDETURTLE
SHOWTURTLE
CLEARSCREEN
CLEAN
Graphics Functions:
XCOR
YCOR
GETANGLE
GETPEN
GETTURTLE
Mathematical:
SUM n1 n2
DIFFERENCE n1 n2
PRODUCT n1 n2
MOD n1 n2
DIV n1 n2
POWER n1 n2
Boolean:
AND b1 b2
OR b1 b2
NOT b
Predicates:
WORDP v
LISTP v
NUMBERP v
GREATER n1 n2
LESS n1 n2
EQUAL v1 v2
Word/List:
FIRST t
LAST t
FPUT t l
BUTFIRST l
WORD w1 w2 w3 ...
LIST t1 t2 t3 ...
CONCAT l1 l2
SENTENCE t1 t2 t3 ...
Our Logo interpreter will only support one of the three windowing
modes: window mode, where the turtle, if it walks off the end of the
screen, just continues going and does not wrap. The two (unsupported)
modes are fence mode where the turtle cannot walk off the end, and
wrap mode. The initial turtle state will be with the turtle hidden,
the pen down, and the turtle in the center of the screen facing
upwards.
All input (both for commands as well as user-input) will be
case-insensitive, and the interpreter needs to handle lists, words,
integers, and boolean values. Also, typing "GoodBye" at the LOGO>
prompt exits the interpreter.
All commands will be enclosed in parentheses, and all lists of
commands will be enclosed in square brackets, so that there is no
longer any need for the keyword "End". Also, all procedures will
return the value of their last command, so that there are no Stop or
Output commands. IF statements should return the value of the last
statement executed, but all looping constructs should return no value.
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