BASIC vs Lambda calculus

BASIC: THE FEELING OF THE GOOD OLD TIMES ! 10 INPUT A 20 B = SIN(A) 30 PRINT "ANSWER: ", B 40 END BASIC USER'S GUIDE: • PRINT 10 PRINT "HELLO WORLD !" 20 END • INPUT 10 INPUT “A=”, A 20 PRINT A 30 END • IF...THEN... Number Comparison: 10 INPUT A 20 IF A＞90 THEN B=“A” 30 PRINT B 40 END Conditional Operators: ＞ greater than ＜ less than ＞= greater than or equal to =＞ equal to or greater than ＜= less than or equal to =＜ equal to or less than = equal to == equal to ＜＞ not equal to != not equal to THEN can be followed by GOTO, GOSUB, INPUT, PRINT. String Comparison: 10 INPUT A 20 IF A=“TOM” THEN PRINT “BOY” 30 END Conditional Operators: = is == is ＜＞ is not != is not • FOR...NEXT... 10 FOR I=1 TO 4 STEP 2 20 PRINT “HELLO”, I 30 NEXT I 40 END STEP specifies the counter increment for each loop. If STEP doesn’t exit, the default increment is 1. FOR...NEXT... loop can be nested. 10 FOR I=1 TO 5 20 FOR J=1 TO 4 30 PRINT I, J 40 NEXT J 50 NEXT I 60 END • GOTO 10 ... 20 ... 30 ... 40 GOTO 10 50 ... • GOSUB 10 PRINT “H” 20 GOSUB 100 30 PRINT “L” 40 END 100 PRINT “A” 110 RETURN • SOUND 10 SOUND C, M, 0.5 The line 10 plays Middle C piano note for 0.5 seconds. Note: C, C#, D, D#, E, F, F#, G, G#, A, A#, B Pitch Range: L (low), M (middle), H (high) Lasting Time: specifies how long a note lasts. C, D, E, F, G, A, B can also be labeled as 1, 2, 3, 4, 5, 6, 7. (C# as 1#). • TEXT 10 TEXT “HELLO”, x, y, size (x,y): position of the string “HELLO”. • CIRCLE 10 CIRCLE x, y, radius (x,y): the center of the circle. • RECTANGLE 10 RECT x, y, width, height (x,y): top-left point of the rectangle. • LINE 10 LINE x1, y1, x2, y2 (x1,y1): the starting point of the line. (x2,y2): the ending point of the line. • POINT 10 POINT x, y (x,y): the position of the point. • CLR: clear the edit window. • CLS: clear the graph window. • DELAY 10 DELAY 0.5 0.5:lasting time in seconds This function is used to suspend execution of a program for a particular time. • CURVE 10 CURVE x, y, radius, 0, PI 0: starting angle PI: ending angle The curve draws clockwise with center (x,y). • Mathematical Functions: SIN(X), COS(X), TAN(X), COT(X), ASIN(X), ACOS(X), ATAN(X), SINH(X), COSH(X), TANH(X), ASINH(X), ACOSH(X), ATANH(X). SQR(X): square root of x. ABS(X): absolute value of x. FCT(X): x factorial. LOG(X): natural logarithm of x. LOG10(X): base-10 logarithm of x. LOG2(X) :base-2 logarithm of x. EXP(X): base-e exponential of x. ERF(X): the error function of x. ERFC(X): the complementary error function of x. ROUND(X) :integral nearest to x. CEIL(X): the smallest integral that is not less than x. FLOOR(X): the largest integral that is not greater than x. TGAMMA(X): the gamma function of x. LGAMMA(X): the natural logarithm of the absolute value of the gamma function of x. • Reserved Variables: INKEY : once a key is pressed, the value of INKEY changes. RND : a random number. PI : π • Some Tips: 1. Undo & Redo typing on iPhone with a shake. 2. Copy an Emoji or some character from other places (like Notes), then paste them on the edit window. 3. Exponentiation is expressed as X^Y.

This app introduces lambda calculus. You can have some understanding for lambda calculus.