--- /dev/null
+.TL
+.de Sy
+.LP
+.IP \fBsyntax\fR 10
+..
+.de PU
+.IP \fBpurpose\fR 10
+..
+.de RM
+.IP \fBremarks\fR 10
+..
+The ABC compiler
+.AU
+Martin L. Kersten
+.AI
+Department of Mathematics and Computer Science.
+.br
+Vrije Universiteit
+.AB
+This manual describes the
+programming language BASIC and its compiler
+included in the Amsterdam Compiler Kit.
+.AE
+.SH
+INTRODUCTION.
+.LP
+The BASIC-EM compiler is an extensive implementation of the
+programming language BASIC.
+The language structure and semantics are modelled after the
+BASIC interpreter/compiler of Microsoft (tr), a detailed comparison
+is provided in appendix A.
+.LP
+The compiler generates code for a virtual machine, the EM machine
+[[ACM, etc]]
+Using EM as an intermediate machine results in a highly portable
+compiler and BASIC code.
+The drawback of EM is that it does not directly reflect one particular
+hardware design, which means that many of
+the low level operations available within
+BASIC are ill-defined or even inapplicable.
+To mention a few, the peek and poke instructions are likely
+to be behave errorneous, while line printer and tapedeck
+primitives are unknown.
+.LP
+This manual is divided into three chapters.
+The first chapter discusses the general language syntax and semantics.
+Chapter two describes the statements available in BASIC-EM.
+Chapter 3 describes the predefined functions,
+ordered alphabetically.
+Appendix A discusses the differences with
+Microsoft BASIC. Appendix B describes all reserved symbols.
+Appendix C lists the error messages in use.
+.sp
+Additional information about EM and the Amsterdam Compiler Kit
+can be obtained from .... and found in ......
+.SH
+SyNTAX NOTATION
+.LP
+The conventions for syntax presentation are as follows:
+.IP CAPS 10
+Items are reserved words, must be input as shown
+.IP <> 10
+Items in lowercase letters enclosed in angular brackets
+are to be supplied by the user.
+.IP [] 10
+Items are optional.
+.IP \.\.\. 10
+Items may be repeated any number of times
+.IP {} 10
+A choice between two or more alternatives. At least one of the entries
+must be chosen.
+.IP | 10
+Vertical bars separate the choices within braces.
+.LP
+All punctuation must be included where shown.
+.NH 1
+GENERAL INFORMATION
+.LP
+The BASIC-EM compiler is designed for a UNIX based environment.
+It accepts a text file with your BASIC program (suffix .b) and generates
+an executable file, called a.out.
+.LP
+Should we call the preprocessor first?
+.NH 2
+LINE FORMAT
+.LP
+A BASIC program consists of a series of lines, starting with a
+positive line number in the range 0 to 65529.
+A line may consists of more then one physical line on your terminal, but must
+is limited to 1024 characters.
+Multiple BASIC statements may be placed on a single line, provided
+they are separated by a colon (:).
+.NH 2
+CONSTANTS
+.LP
+The BASIC compiler character set is comprised of alphabetic
+characters, numeric characters, and special characters shown below.
+.DS
+= + - * / ^ ( ) % # $ \\ _
+! [ ] , . ; : & ' ? > < \\ (blanc)
+.DE
+.LP
+BASIC uses two different types of constants during processing:
+numeric and string constants.
+.br
+A string constant is a sequence of characters taken from the ASCII
+character set enclosed by double quotation marks.
+.br
+Numeric constants are positive or negative numbers, grouped into
+five different classes.
+.IP "a) integer constants" 25
+Whole numbers in the range of -32768 and 32767. Integer constants do
+not contain decimal points.
+.IP "b) fixed point constants" 25
+Positive or negative real numbers, i.e. numbers with a decimal point.
+.IP "c) floating point constants" 25
+Real numbers in scientific notation. A floating point constant
+consists of an optional signed integer or fixed point number
+followed by the letter E (or D) and an optional signed integer
+(the exponent).
+The allowable range of floating point constants is 10^-38 to 10^+38.
+.IP "d) Hex constants" 25
+Hexadecimal numbers, denoted by the prefix &H.
+.IP "d) Octal constants" 25
+Octal numbers, denoted by the prefix &O.
+.NH 2
+VARIABLES
+.LP
+Variables are names used to represent values in a BASIC program.
+A variable is assigned a value by assigment specified in the program.
+Before a variable is assigned its value is assumed to be zero.
+.br
+Variable names are composed of letters, digits or the decimal point,
+starting with a letter. Up to 40 characters are significant.
+A variable name be be followed by any of the following type
+declaration characters:
+.IP % 5
+Defines an integer variable
+.IP ! 5
+Defines a single precision variable (see below)
+.IP # 5
+Defines a double precision variable
+.IP $ 5
+Defines a string variable.
+.LP
+NOTE: Two variables with the same name but different type is
+considered illegal (DONE?).
+.LP
+Beside single valued variables, values may be grouped
+into tables or arrays.
+Each element in an array is referenced by the array name and an index,
+such a variable is called a subscripted variable.
+An array has as many subscripts as there are dimensions in the array,
+the maximum of which is 11.
+.br
+If a variable starts with FN it is assumed to be a call to a user defined
+function.
+.br
+A variable name may not be a reserved word nor the name
+of a predefined function.
+A list of all reserved identifiers is included as Appendix ?.
+.NH 2
+EXPRESSIONS
+.LP
+BASIC-EM differs from Microsoft BASIC in supporting floats in one precision
+only (due to EM).
+All floating point constants have the same precision, i.e. 16 digits.
+.LP
+When necessary the compiler will convert a numeric value from
+one type to another.
+A value is always converted to the precision of the variable it is assigned
+to.
+When a floating point value is converted to an integer the fractional
+portion is rounded.
+In an expression all values are converted to the same degree of precision,
+i.e. that of the most precise operand.
+.br
+Division by zero results in the message "Division by zero".
+If overflow (or underflow) occurs, the "Overflow (underflow)" message is
+displayed and execution is terminated (contrary to Microsoft).
+.SH
+Arithmetic
+.LP
+The arithmetic operators in order of precedence,a re:
+.DS L
+\^ Exponentiation
+- Negation
+*,/,\\,MOD Multiplication, Division, Remainder
++,- Addition, Substraction
+.DE
+The operator \\\\ denotes integer division, its operands are rounded to
+integers before the operator is applied.
+Modulus arithmetic is denoted by the operator MOD, which yields the
+integer value that is the remainder of an integer division.
+.br
+The order in which operators are performed can be changec with parentheses.
+.SH
+Relational
+.LP
+The relational operators in order of precedence, are:
+.DS
+= Equality
+<> Inequality
+< Less than
+> Greater than
+<= Less than or equal to
+>= Greater than or equal to
+.DE
+The relational operators are used to compare two values and returns
+either "true" (-1) or "false" (0) (See IF statement).
+The precedence of the relational operators is lower
+then the arithmetic operators.
+.SH
+Logical
+.LP
+The logical operators performs tests on multiple relations, bit manipulations,
+or Boolean operations.
+The logical operators returns a bitwise result ("true" or "false").
+In an expression, logical operators are performed after the relational and
+arithmetic operators.
+The logical operators work by converting their operands to signed
+two-complement integers in the range -32768 to 32767.
+.DS
+NOT Bitwise negation
+AND Bitwise and
+OR Bitwise or
+XOR Bitwise exclusive or
+EQV Bitwise equivalence
+IMP Bitwise implies
+.DE
+.SH
+Functional
+.LP
+A function is used in an expression to call a system or user defined
+function.
+A list of predefined functions is presented in chapter 3.
+.SH
+String operations
+.LP
+Strings can be concatenated by using +. Strings can be compared with
+the relational operators. String comparison is performed in lexicographic
+order.
+.NH 2
+ERROR MESSAGES
+.LP
+The occurence of an error results in termination of the program
+unless an ON....ERROR statement has been encountered.
+.NH 1
+B-EM STATEMENTS
+.LP
+This chapter describes the statements available within the BASIC-EM
+compiler. Each description is formatted as follows:
+.Sy
+Shows the correct syntax for the statement. See introduction of
+syntax notation above.
+.PU
+Describes the purpose and details of the instructions.
+.RM
+Describes special cases, deviation from Microsoft BASIC etc.
+.LP
+.NH 2
+CALL
+.Sy
+CALL <variable name>[(<argument list>)]
+.PU
+The CALL statement provides the means to execute procedures
+and functions written in another language included in the
+Amsterdam Compiler Kit.
+The argument list consist of (subscripted) variables.
+The BASIC compiler pushes the address of the arguments on the stack in order
+of encounter.
+.RM
+Not yet available
+.NH 2
+CLOSE
+.Sy
+CLOSE [[#]<file number>[,[#]<file number...>]]
+.PU
+To terminate I/O on a disk file.
+<file number> is the number associated with the file
+when it was OPENed (See OPEN). Ommission of parameters results in closing
+all files.
+.sp
+The END statement and STOP statement always issue a CLOSE of
+all files.
+.NH 2
+DATA
+.Sy
+DATA <list of constants>
+.PU
+DATA statements are used to construct a data bank of values that are
+accessed by the program's READ statement.
+DATA statements are non-executable,
+the data items are assembled in a data file by the BASIC compiler.
+This file can be replaced, provided the layout remains
+the same (otherwise the RESTORE won't function properly).
+.sp
+The list of data items consists of numeric and string constants
+as discussed in section 1.
+Moreover, string constants starting with a letter and not
+containing blancs, newlines, commas, colon need not be enclosed with
+the string quotes.
+.sp
+DATA statements can be reread using the RESTORE statement.
+.NH 2
+DEF FN
+.Sy
+DEF FN<name> [(<parameterlist>)]=<expression>
+.PU
+To define and name a function that is written by the user.
+<name> must be an identifier and should be preceded by FN,
+which is considered integral part of the function name.
+<expression> defines the expression to be evaluated upon function call.
+.sp
+The parameter list is comprised of a comma separated
+list of variable names, used within the function definition,
+that are to replaced by values upon function call.
+The variable names defined in the parameterlist, called formal
+parameters, do not affect the definition and use of variables
+defined with the same name in the rest of the BASIC program.
+.sp
+A type declaration character may be suffixed to the function name to
+designate the data type of the function result.
+.NH 2
+DEFINT/SNG/DBL/STR
+.Sy
+DEF<type> <range of letters>
+.PU
+Any undefined variable starting with the letter included in the range of
+letters is declared of type <type> unless a type declaration character
+is appended.
+The range of letters is a comma separated list of characters and
+character ranges (<letter>-<letter>).
+.NH 2
+DIM
+.Sy
+DIM <list of subscripted variable>
+.PU
+The DIM statement allocates storage for subscripted variables.
+If an undefined subscripted variable is used
+the maximum value of the array subscript(s) is assumed to be 10.
+A subscript out of range is signalled by the program (when RCK works)
+The minimum subscript value is 0, unless the OPTION BASE statement has been
+encountered.
+.sp
+All variables in a subscripted variable are initially zero.
+.sp
+BUG. Multi-dimensional arrays MUST be defined.
+.NH 2
+END
+.Sy
+END
+.PU
+END terminates a BASIC program and returns to the UNIX shell.
+An END statement at the end of the BASIC program is optional.
+.NH 2
+ERR and ERL
+.PU
+Whenever an error occurs the variable ERR contains the
+error number and ERL the BASIC line where the error occurred.
+The variables are usually used in error handling routines
+provided by the user.
+.NH 2
+ERROR
+.Sy
+ERROR <integer expression>
+.PU
+To simulate the occurrence of a BASIC error.
+To define your own error code use a value not already in
+use by the BASIC runtime system.
+The list of error messages currently in use
+can be found in appendix B.
+.NH 2
+FIELD
+.PU
+To be implemented.
+.NH 2
+FOR...NEXT
+.Sy
+FOR <variable>= <low>TO<high>[STEP<size>]
+.br
+ ......
+.br
+NEXT [<variable>][,<variable>...]
+.PU
+The FOR statements allows a series of statements to be performed
+repeatedly. <variable> is used as a counter. During the first
+execution pass it is assigned the value <low>,
+an arithmetic expression. After each pass the counter
+is incremented with the step size <size>, an expression.
+Ommission of the step size is intepreted as an increment of 1.
+Execution of the program lines specified between the FOR and the NEXT
+statement is terminated as soon as <low> is greater than <high>
+.sp
+The NEXT statement is labeled with the name(s) of the counter to be
+incremented.
+.sp
+The body of the FOR statement is skipped when the initial value of the
+loop times the sign of the step exceeds the value of the highest value
+times the sign of the step.
+.sp
+The variables mentioned in the NEXT statement may be ommitted, in which case
+the variable of increment the counter of the most recent FOR statement.
+If a NEXT statement is encountered before its corresponding FOR statement,
+the error message "NEXT without FOR" is generated.
+.NH 2
+GET
+.Sy
+GET [#]<file number>[, <record number>]
+.PU
+To be implemented.
+.NH 2
+GOSUB...RETURN
+.Sy
+GOSUB <line number
+ ...
+.br
+RETURN
+.PU
+The GOSUB statement branches to the first statement of a subroutine.
+The RETURN statement cause a branch back to the statement following the
+most recent GOSUB statement.
+A subroutine may contain more than one RETURN statement.
+.sp
+Subroutines may be called recursively.
+Nesting of subroutine calls is limited, upon exceeding the maximum depth
+the error message "XXXXX" is displayed.
+.NH 2
+GOTO
+.Sy
+GOTO <line number>
+.PU
+To branch unconditionally to a specified line in the program.
+If <line number> does not exists, the compilation error message
+"Line not defined" is displayed.
+.RM
+Microsoft BASIC continues at the first line
+equal or greater then the line specified.
+.NH 2
+IF...THEN
+.Sy
+.br
+IF <expression> THEN {<statements>|<line number>}
+[ELSE {<statements>|<line number>}]
+.br
+.Sy
+IF <expression> GOTO <line number>
+[ELSE {<statements>|<line number>}]
+.PU
+The IF statement is used
+to make a decision regarding the program flow based on the
+result of the expressions.
+If the expression is not zero, the THEN or GOTO clause is
+executed. If the result of <expression> is zero, the THEN or
+GOTO clause is ignored and the ELSE clause, if present is
+executed.
+.br
+IF..THEN..ELSE statements may be nested.
+Nesting is limited by the length of the line.
+The ELSE clause matches with the closests unmatched THEN.
+.sp
+When using IF to test equality for a value that is the
+result of a floating point expression, remember that the
+internal representation of the value may not be exact.
+Therefore, the test should be against a range to
+handle the relative error.
+.RM
+Microsoft BASIC allows a comma before THEN.
+.NH 2
+INPUT
+.Sy
+INPUT [;][<"prompt string">;]<list of variables>
+.PU
+An INPUT statement can be used to obtain values from the user at the
+terminal.
+When an INPUT statement is encountered a question mark is printed
+to indicate the program is awaiting data.
+IF <"prompt string"> is included, the string is printed before the
+the question mark. The question mark is suppressed when the prompt
+string is followed by a comma, rather then a semicolon.
+.sp
+For each variable in the variable a list a value should be supplied.
+Data items presented should be separated by a comma.
+.sp
+The type of the variable in the variable list must aggree with the
+type of the data item entered. Responding with too few or too many
+data items causes the message "?Redo". No assignment of input values
+is made until an acceptable response is given.
+.RM
+The option to disgard the carriage return with the semicolon after the
+input symbol is not yet implemented.
+.NH 2
+INPUT [#]
+.Sy
+INPUT #<file number>,<list of variables>
+.PU
+The purpose of the INPUT# statement is to read data items from a sequential
+file and assign them to program variables.
+<file number> is the number used to open the file for input.
+The variables mentioned are (subscripted) variables.
+The type of the data items read should aggree with the type of the variables.
+A type mismatch results in the error message "XXXXX".
+.sp
+The data items on the sequential file are separated by commas and newlines.
+In scanning the file, leading spaces, new lines, tabs, and
+carriage returns are ignored. The first character encountered
+is assumed to be the state of a new item.
+String items need not be enclosed with double quotes, provided
+it does not contain spaces, tabs, newlines and commas,
+.RM
+Microsoft BASIC won't assign values until the end of input statement.
+This means that the user has to supply all the information.
+.NH 2
+LET
+.Sy
+[LET]<variable>=<expression>
+.PU
+To assign the value of an expression to a (subscribted) variable.
+The type convertions as dictated in section 1.X apply.
+.NH 2
+LINE INPUT
+.Sy
+LINE INPUT [;][<"prompt string">;]<string variable>
+.PU
+An entire line of input is assigned to the string variable.
+See INPUT for the meaning of the <"prompt string"> option.
+.NH 2
+LINE INPUT [#]
+.Sy
+LINE INPUT #<file number>,<string variable>
+.PU
+Read an entire line of text from a sequential file <file number>
+and assign it to a string variable.
+.NH 2
+LSET and RSET
+.PU
+To be implemented
+.NH 2
+MID$
+.Sy
+MID$(<string expr1>,n[,m])=<string expr2>
+.PU
+To replace a portion of a string with another string value.
+The characters of <string expr> replaces characters in <string expr1>
+starting at position n. If m is present, at most m characters are copied,
+otherwise all characters are copied.
+However, the string obtained never exceeds the length of string expr1.
+.NH 2
+ON ERROR GOTO
+.Sy
+ON ERROR GOTO <line number>
+.PU
+To enable error handling within the BASIC program.
+An error may result from arithmetic errors, disk problems, interrupts, or
+as a result of the ERROR statement.
+After printing an error message the program is continued at the
+statements associated with <line number>.
+.sp
+Error handling is disabled using ON ERROR GOTO 0.
+Subsequent errors result in an error message and program termination.
+.NH 2
+ON...GOSUB and ON ...GOTO
+.Sy
+ON <expression> GOSUB <list of line numbers>
+ON <expression> GOTO <list of line numbers>
+.PU
+To branch to one of several specified line numbers or subroutines, based
+on the result of the <expression>. The list of line numbers are considered
+the first, second, etc alternative. Branching to the first occurs when
+the expression evaluates to one, to the second alternative on two, etc.
+If the value of the expression in zero or greater than the number of alternatives, processing continues at the first statement following the ON..GOTO
+(ON GOSUB) statement.
+When the expression results in a negative number the
+an "Illegal function call" error occurs.
+.NH 2
+OPEN
+.NH 2
+OPTION BASE
+.Sy
+OPTION BASE n
+.PU
+To declare the lower bound of subsequent array subscripts as either
+0 or 1. The default lower bound is zero.
+.NH 2
+POKE
+.Sy
+POKE <expr1>,<expr2>
+.PU
+To poke around in memory. The use of this statement is not recommended,
+because it requires full understanding of both
+the implementation of the Amsterdam
+Compiler Kit and the hardware characteristics.
+.NH 2
+PRINT [USING]
+.NH 2
+PUT
+.PU
+To be implemented
+.NH 2
+RANDOMIZE
+.Sy
+RANDOMIZE [<expression>]
+.PU
+To reset the random seed. When the expression is ommitted, the system
+will ask for a value between -32768 and 32767.
+The random number generator returns the same sequence of values provided
+the same seed is used.
+.NH 2
+READ
+.Sy
+READ <list of variables>
+.PU
+To read values from the DATA statements and assign them to variables.
+The type of the variables should match to the type of the items being read,
+otherwise a "Syntax error" occurs.
+.NH 2
+REM
+.Sy
+REM <remark>
+.PU
+To include explantory information in a program.
+The REM statements are not executed.
+A single quote has the same effect as : REM, which
+allows for the inclusion of comment at the end of the line.
+.RM
+Microsoft BASIC does not allow REM statements as part of
+DATA lines.
+.NH 2
+RESTORE
+.Sy
+RESTORE [<line number>]
+.PU
+To allow DATA statements to be re-read from a specific line.
+After a RESTORE statement is executed, the next READ accesses
+the first item of the DATA statements.
+If <line number> is specified, the next READ accesses the first
+item in the specified line.
+.sp
+Note that data statements result in a sequential datafile generated
+by the compiler, being read by the read statements.
+This data file may be replaced using the operating system functions
+with a modified version, provided the same layout of items
+(same number of lines and items per line) is used.
+.NH 2
+STOP
+.Sy
+STOP
+.PU
+To terminate the execution of a program and return to the operating system
+command interpreter. A STOP statement results in the message "Break in line
+???"
+.NH 2
+SWAP
+.Sy
+SWAP <variable>,<variable>
+.PU
+To exchange the values of two variables.
+.NH 2
+TRON/TROFF
+.Sy
+TRON
+.Sy
+TROFF
+.PU
+As an aid in debugging the TRON statement results in a program
+listing each line being interpreted. TROFF disables generation of
+this code.
+.NH 2
+WHILE...WEND
+.Sy
+WHILE <expression>
+ .....
+WEND
+.PU
+To execute a series of BASIC statements as long as a conditional expression
+is true. WHILE...WEND loops may be nested.
+.NH 2
+WRITE
+.Sy
+WRITE [<list of expressions>]
+.PU
+To write data at the terminal in DATA statement layout conventions.
+The expressions should be separated by commas.
+.NH 2
+WRITE #
+.Sy
+WRITE #<file number> ,<list of expressions>
+.PU
+To write a sequential data file, being opened with the "O" mode.
+The values are being writting using the DATA statements layout conventions.
+.NH
+FUNCTIONS
+.LP
+.IP ABS(X) 12
+Returns the absolute value of expression X
+.IP ASC(X$) 12
+Returns the numeric value of the first character of the string.
+If X$ is not initialized an "Illegal function call" error
+is returned.
+.IP ATN(X) 12
+Returns the arctangent of X in radians. Result is in the range
+of -pi/2 to pi/2.
+.IP CDBL(X) 12
+Converts X to a double precision number.
+.IP CHR$(X) 12
+Converts the integer value X to its ASCII character.
+X must be in the range of 0 to 127.
+It is used for cursor addressing and generating bel signals.
+.IP CINT(X) 12
+Converts X to an integer by rounding the fractional portion.
+If X is not in the range -32768 to 32767 an "Overflow"
+error occurs.
+.IP COS(X) 12
+Returns the cosine of X in radians.
+.IP CSNG(X) 12
+Converts X to a double precision number.
+.IP CVI(<2-bytes>) 12
+Convert two byte string value to integer number.
+.IP CVS(<4-bytes>) 12
+Convert four byte string value to single precision number.
+.IP CVD(<8-bytes>) 12
+Convert eight byte string value to double precision number.
+.IP EOF[(<file-number>)] 12
+Returns -1 (true) if the end of a sequential file has been reached.
+.IP EXP(X) 12
+Returns e(base of natural logarithm) to the power of X.
+X should be less then 10000.0.
+.IP FIX(X) 12
+Returns the truncated integer part of X. FIX(X) is
+equivalent to SGN(X)*INT(ABS(X)).
+The major difference between FIX and INT is that FIX does not
+return the next lower number for negative X.
+.IP HEX$(X) 12
+Returns the string which represents the hexadecimal value of
+the decimal argument. X is rounded to an integer using CINT
+before HEX$ is evaluated.
+.IP INT(X) 12
+Returns the largest integer <= X.
+.IP INPUT$(X[,[#]Y]) 12
+Returns the string of X characters read from the terminal or
+the designated file.
+.IP LEX(X$) 12
+Returns the number of characters in the string X$.
+Non printable and blancs are counted too.
+.IP LOC(<file\ number>) 12
+For sequential files LOC returns
+position of the read/write head, counted in number of bytes.
+For random files the function returns the record number just
+read or written from a GET or PUT statement.
+If nothing was read or written 0 is returned.
+.IP LOG(X) 12
+Returns the natural logarithm of X. X must be greater than zero.
+.IP MID$(X,I,[J]) 12
+To be implemented.
+.IP MKI$(X) 12
+Converts an integer expression to a two-byte string.
+.IP MKS$(X) 12
+Converts a single precision expression to a four-byte string.
+.IP MKD$(X) 12
+Converts a double precision expression to a eight-byte string.
+.IP OCT$(X) 12
+Returns the string which represents the octal value of the decimal
+argument. X is rounded to an integer using CINT before OCTS is evaluated.
+.IP PEEK(I) 12
+Returns the byte read from the indicated memory. (Of limited use
+in the context of ACK)
+.IP POS(I) 12
+Returns the current cursor position. To be implemented.
+.IP RIGHT$(X$,I)
+Returns the right most I characters of string X$.
+If I=0 then the empty string is returned.
+.IP RND(X) 12
+Returns a random number between 0 and 1. X is a dummy argument.
+.IP SGN(X) 12
+If X>0 , SGN(X) returns 1.
+.br
+if X=0, SGN(X) returns 0.
+.br
+if X<0, SGN(X) returns -1.
+.IP SIN(X) 12
+Returns the sine of X in radians.
+.IP SPACE$(X) 12
+Returns a string of spaces length X. The expression
+X is rounded to an integer using CINT.
+.IP STR$(X)
+Returns the string representation value of X.
+.IP STRING$(I,J) 12
+Returns thes string of length Iwhose characters all
+have ASCII code J. (or first character when J is a string)
+.IP TAB(I) 12
+Spaces to position I on the terminal. If the current
+print position is already beyond space I,TAB
+goes to that position on the next line.
+Space 1 is leftmost position, and the rightmost position
+is width minus 1. To be used within PRINT statements only.
+.IP TAN(X) 12
+Returns the tangent of X in radians. If TAN overflows
+the "Overflow" message is displayed.
+.IP VAL(X$) 12
+Returns the numerical value of string X$.
+The VAL function strips leading blanks and tabs from the
+argument string.
+.SH
+APPENDIX A DIFFERENCES WITH MICROSOFT BASIC
+.LP
+The following list of Microsoft commands and statements are
+not recognized by the compiler.
+.DS
+SPC
+USR
+VARPTR
+AUTO
+CHAIN
+CLEAR
+CLOAD
+COMMON
+CONT
+CSAVE
+DELETE
+EDIT
+ERASE
+FRE
+KILL
+LIST
+LLIST
+LOAD
+LPRINT
+MERGE
+NAME
+NEW
+NULL
+RENUM
+RESUME
+RUN
+SAVE
+WAIT
+WIDTH LPRINT
+.DE
+Some statements are in the current implementation not available,
+but will be soon. These include:
+.DS
+CALL
+DEFUSR
+FIELD
+GET
+INKEY
+INPUT$
+INSTR$
+LEFT$
+LSET
+RSET
+PUT
+.DE
public / ack.git / commitdiff