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Text File | 1994-02-08 | 13.3 KB | 388 lines

>>> ASC - function to return the ascii code of an argument Example: PRINT "The ASCII code of A is" ASC "A" >>> ASCII - function to return the ascii code of an argument Same as ASC >>> BE - Placeholder for syntax. This command does nothing Placeholders are dummy commands that help make the syntax more natural. You can use this, as well as other placeholders anywhere in a statement and it will simply be ignored. Example: LET X BE 1 >>> CALC - Calculates whatever expression follows. This command performs the same function as EVAL, CASE, and WHAT. BozoL will not automatically calculate arithmetic expressions in a statement. If you said PRINT 1+1 BozoL will literally print "1+1". In order to evaluate an expression you must use CALC, EVAL, CASE or WHAT before the expression. These keywords can be intermixed and used multiple times in a statement. There is no difference between the four of them. Having a choice just makes the syntax easier to read and remember. Example: PRINT CALC 1+1 (would print 2) Example: IF EVAL A>B: GOSUB 10 (would jump to 10 if IF CASE A=B: GOSUB 10 the expression is true) Example: PRINT WHAT A+B IS (would print A+B. The keyword IS is also a placeholder and does nothing) >>> CASE - Calculates whatever expression follows. Same as CALC >>> CHR - Returns the character string of an ASCII code Example: PRINT CHR 7 >>> CLS - Clears the screen Example: IF finished:CLS:END >>> COLOR - Sets the current color selection Just like BASIC. >>> CR - Returns a carriage return Example: PRINT "Hello" CR CR CR "Goodbye!" >>> END - Exits the BozoL interpreter. End exits the subroutine PROGRUN and terminates the program. >>> EQUAL - Placeholder for syntax. This command does nothing LET and SET are used to assign values to variables. They only need two arguments, the variable, and the value for it. Since LET A B would be unclear, you can use a placeholder, such as EQUAL to make the syntax a little more readable: Example: LET A EQUAL B >>> EQUALS - Tests two string values, returns true if they are the same This function does not make for a readable syntax. It is identical to the function SAME Example: QUIT IF EQUALS UCASE INKEY "X" (quit if X is in keyboard) Example: BE UNTIL NOT EQUALS INKEY "" (wait for a key to be pressed) >>> EVAL - Calculates whatever expression follows. Same as CALC >>> FALSE - Returns a logical false (0) Example: PRINT "Wheeeeeee" WHILE WHAT LEN INKEY = IS FALSE >>> GOSUB - Jumps to a subroutine which terminates with RETURN This works the same as BASIC's GOSUB statement. You can nest up to 32 GOSUBs. GOSUB must be followed by a line number or a label. Example: PRINT "Starting here" GOSUB Middle PRINT "Ending here!" END Middle: PRINT "This is the middle!" : RETURN >>> GOTO - Jumps to a line number or label. This works just like the BASIC GOTO statement. You must be aware that BozoL does not inherantly label line numbers, so unless you are sure that the line number is not going to change (by adding or deleting a line above it) you should use labels. Example: PRINT "Starting here." GOTO TheEnd PRINT "Never gets here!" TheEnd: PRINT "This is the end!" >>> IF - Test and expression and continue if true This is similar to the BASIC IF statement, however it has some strict limitations and differences. First, there is no THEN statement. Simply follow IF with an expression and then a colon. If the expression is true, the remainder of the line will be executed. There is also no ELSE keyword. Example: IF EVAL A=B: GOSUB 100 A second use for IF is to place the IF expression at the very end of the line. If the expression is false, the preceeding statements not separated by colons will be aborted. Example: GOSUB 100 IF EVAL A=B >>> IN - Placeholder for syntax. This command does nothing Example: SAVE IN "TEST.PRG" >>> INKEY - Returns next character in keyboard buffer, if any INKEY does not pause. If one or more characters are waiting in the keyboard buffer INKEY will return that character. If no characters are waiting INKEY will return a null. Example: BE UNTIL LEN INKEY Remember that BE is just a placehoder. The expression UNTIL LEN INKEY would work just the same. >>> INPUT - Gets a line of input from the user into a variable You can follow INPUT by a valid sequence of items to print. The final parameter of INPUT must be a variable to contain the input line after it has been typed. Unlike BASIC, the INPUT expression may contain variables and functions. Example: INPUT "What is your name? ",NAME This would prompt the user (What is your name?) and then wait while the user responds. When the user presses ENTER, the response would be contained in the variable NAME. You can use placeholders or a space to delimit this line. Example: INPUT "What is your name? " TO NAME >>> IS - Placeholder for syntax. This command does nothing Example: GOTO 100 IF IS SAME A,B >>> LCASE - Returns the lower case of an argument Example: IF SAME LCASE INKEY,"y": END >>> LEFT - Returns specified number of characters from left of string Example: PRINT LEFT "Erik",3 This would print "Eri" on the screen. Not that a comma is also just a placeholder and can be substituted with a space or a semicolon. >>> LEN - Returns the length of a string expression Example: BE UNTIL LEN INKEY This statement would loop until the length of INKEY was no longer zero. >>> LET - Assigns a value to a variable (same as SET) Example: LET A EQUAL B Note that you cannot use the equals sign (=) to assign a value to a variable. The equals sign is only used in arithmetic expressions to test whether one number is equal to another. example: LET A BE EQUAL TO B LET only requires two parameters, a varable and a value. You can use placeholders, a comma, or just a space to separate them. The above example is identical to LET A,B >>> LIST - lists the program currently in memory to the screen LIST by itself will type the whole program to the screen. LIST followed by a line number will display that line. List followed by two line numbers will display all of the numbers in between. Example: LIST 1 TO 100 Note the placeholder TO. You could also just say LIST 1 100 or LIST 1,100 and it would work the same. >>> LOAD - Reads a program file from disk into memory. Example: LOAD "TEST.PRG" >>> LOCATE - Positions the cursor on the screen. Example: LOCATE 10,10 : PRINT "Hi there!" >>> LOWER - Returns the lower case of a string expression Same as LCASE >>> LTRIM - Trims leading spaces from a string expression. Example: PRINT LTRIM RTRIM " Hello! " >>> MID - Returns a middle portion of a string expression Example: PRINT MID "testing",2,4 This example would print "stin" on the screen. The syntax for MID is the same as BASIC's MID$ function. If the third parameter is ommitted, MID will return the remainder of the string. Example: PRINT MID "testing",2 Would print "esting" on the screen. >>> NOT - Returns a logical NOT value of an argument. Example: PRINT NOT TRUE This would print 0 (opposite of TRUE, which is -1) on the screen. Example: IF NOT SAME A,B: PRINT "They don't match!" >>> PRINT - Prints an expression on the screen Print can be followed by any number of arguments separated by spaces, commas, or placeholders. Example: PRINT "This" "is" "a" "test" would print "Thisisatest" on the screen. PRINT always outputs a carriage return at the end of the print line. To print without a carriage return, use PROMPT. >>> PROMPT - Prints to the screen without a carriage return PROMPT works the same as print except the cursor is not advanced to the next line after the line to be printed has been output. Example: PROMPT "Please enter your name:" >>> QUIT - Exits the BozoL interpreter Same as END >>> RETURN - Exits a subroutine entered with GOSUB Up to 32 GOSUB-RETURN pairs can be nested in BozoL. RETURN jumps to the line immediately following the most recent GOSUB. >>> RIGHT - Returns a number of characters from the right of a string. Example: PRINT RIGHT "Erik",2 This would print "ik" in the screen. >>> RTRIM - Removes trailing spaces from a string. See LTRIM >>> RUN - Executes an interpreted program RUN by itself will execute the program currently in memory from the beginning. If RUN is followed by the name of a BozoL program file, the file will be loaded and then run. >>> SAME - Returns true if two string expressions match. Same as EQUALS >>> SAVE - Writes the current program in memory to disk. SAVE must be followed by a file name. Example: SAVE "test.prg" >>> SET - Assigns a value to a variable (same as LET) Example: SET Name TO "Erik Olson" See the entry for LET >>> SUBSTR - Returns the middle portion of a string expression Same as MID >>> TAB - Returns a TAB character. Using TAB in an expression would be just like using CHR 9. Example: PRINT "Hello" TAB "World" Would print "Hello World" on the screen. >>> TO - Placeholder for syntax. This command does nothing Use TO wherever you like to make the syntax of BozoL more readable. Example: SET A TO 1 >>> TRUE - Returns a logical TRUE (-1) Example: SET A TO TRUE >>> UCASE - Returns the upper case of a string expression Example: TO BE UNTIL IS SAME UPPER INKEY "X" This would wait until the user presses "x" or "X" >>> UNTIL - Continues to iterate until an expression is true. Place UNTIL at the beginning of a line with multiple statements separated by colons (:) or at the end of a set of statements that are not separated by colons. The entire line will continue to iterate until the expression which follows UNTIL evalutes true. Example: UNTIL CALC A=10: SET A TO CALC A+1: PRINT A This would print the numbers 1 through 10 on the screen. Using the "no-colon" syntax, this expression would look like this: PRINT A SET A TO CALC A+1 UNTIL CALC A=10 >>> UPPER - Returns the upper case of a string expression Same as UCASE >>> WHAT - Same as CALC, EVAL, and CASE >>> WHILE - Continues to iterate while an expression is true. This is very similar to UNTIL, except it iterates until the expression evaluates to false. Place WHILE at the beginning of a line with multiple statements separated by colons (:) or at the end of a set of statements that are not separated by colons. The entire line will continue to iterate while the expression which follows WHILE evalutes true. Example: WHILE CALC A<10: SET A TO CALC A+1: PRINT A This would print the numbers 1 through 9 on the screen. Using the "no-colon" syntax, this expression would look like this: PRINT A SET A TO CALC A+1 WHILE CALC A<10 >>> WITH - Placeholder for syntax. This command does nothing Example: REPLACE "BozoL" WITH "My Language" IN "BOZOL.DOC" REPLACE is not a command in BozoL, but if you wanted to make it one all you would have to do is add it to the language. In this example we have a command called REPLACE which is used to perform a search and replace in a file on disk. The use of WITH and IN is arbitrary but makes the syntax of this statement much more memorable.