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.