* Section 1: Differences from TRL [1]
* Section 2: Summary of expression syntax
* Section 3: Summary of instructions
* Section 4: Summary of builtin functions
[1] The Rexx Language, a practical approach to programming
M. F. Cowlishaw
Englewood Cliffs 1985
The following are all nonstandard features of REXX-imc * Rejection of labels ending with dot (in case of confusion between function.(args) and stem.(tail)) * Compound variable accesses of the form "stem.'string constant'" and stem.(expression) * Acceptance of any non-zero number for logical truth, rather than just 1 * "SAYN expression" to output lines without carriage return * "SELECT expression" to switch on a value * "END SELECT" * "PARSE VALUE" with multiple strings separated by commas * "PROCEDURE HIDE" * The following functions: chdir getcwd getenv putenv system userid rxfuncadd rxfuncdrop rxfuncquery plus these I/O functions: open close fdopen popen pclose fileno ftell * error messages 80-210, -1 and -3.
Strings: "String constants" 'enclosed in quotes'
Hex strings: '616263 64'x
Numbers: 123.4e-56
Constant symbols: .abc 1d4 7!
Simple symbols: foo bar xyz3
Stems: array.
Compound symbols: c.3 element.bar.45
Operators: arithmetic: + - * / ** (to-power) % (div) // (mod)
string: [abuttal] [space] || (concatenation)
logical: \ (not) & (and) | (or) && (xor)
comparison: = > < <> <= >= \> \< \=
== >> << <<= >>= \>> \<< \== (strong comparison)
Function calls: fn(1,2,3) bar(,5) 'DATE'()
/* this is a comment */
expression - execute a host command
symbol=value - assignment
ADDRESS [VALUE] [environment] - change the current environment
ADDRESS environment command - execute a command in an environment
CALL name [arg][,[arg],...]] - call a function or subroutine
CALL ON condition [NAME symbol]- turn on condition handling
CALL OFF condition - turn off condition handling
condition = ERROR | FAILURE | NOTREADY | HALT
DO [ symbol=start [TO finish] ] [WHILE expression_w]
[ [BY step ] ]
[ [FOR count ] ] [UNTIL expression_u]
[ expression_c ] [FOREVER ]
- block or repetitive block instruction
DROP symbol [symbol...] - de-assignment
END [symbol] - end block or repetitive block instruction
EXIT [expression] - exit program or external function
IF expression [;] THEN [;] statement [ ; ELSE [;] statement]
- conditional instruction
INTERPRET expression - dynamically execute a string
ITERATE [symbol] - continue repetitive block
LEAVE [symbol] - leave repetitive block
NOP - do nothing
NUMERIC DIGITS n - set parameters for numeric formatting
NUMERIC FUZZ n
NUMERIC FORM SCIENTIFIC
| ENGINEERING
| "string constant"
| [VALUE] expression
OPTIONS expression - Control system-dependent things
[PARSE [UPPER]] ARG template
[PARSE [UPPER]] PULL [template]
PARSE [UPPER] LINEIN [template]
PARSE [UPPER] SOURCE template
PARSE [UPPER] VERSION template
PARSE [UPPER] NUMERIC template
PARSE [UPPER] VAR symbol template
PARSE [UPPER] VALUE expression WITH template
template -> [firstPosition] assignments [assignments]
assignments -> [nextPosition] varlist [stopPosition]
varlist -> varname ' ' [varlist]
varname -> "non-constant symbol"
| '.'
firstPosition -> position
nextPosition -> position [nextPosition]
stopPosition -> position
position -> searchPosition
| absPosition
| relPosition
| '(' "expression" ')'
searchPosition -> "string constant"
absPosition -> "integer"
| '=' numexpr
relPosition -> '+' numexpr
| '-' numexpr
numexpr -> "integer"
| '(' "integer expression" ')'
PROCEDURE - hide the caller's symbols
PROCEDURE EXPOSE var1 [var2...]
PROCEDURE HIDE var1 [var2...]
PUSH expression - stack a value in LIFO order
QUEUE expression - stack a value in FIFO order
RETURN [value] - return from a function or subroutine
SAY [expression] - echo data
SAYN expression - echo data without newline
SELECT [expression]
WHEN expression THEN statements
WHEN expression THEN statements
...
[OTHERWISE statements]
END [SELECT] - switch on a list of conditions
SIGNAL [VALUE] name - jump to a label
SIGNAL ON condition [NAME symbol] - turn on condition handling
SIGNAL OFF condition - turn off condition handling
condition = ERROR | FAILURE | NOTREADY | HALT | SYNTAX | NOVALUE
TRACE [symbol] - control program tracing. Values are:
TRACE "string" A (all clauses) C (commands) E (error)
TRACE VALUE expression F (failure) I (intermediate values)
L (labels) N (normal, =F) O (off)
R (results)
Standard functions
ABBREV(information,info[,length]) - check for valid abbreviations
ABS(number) - return the absolute value
ADDRESS() - return the current environment
ARG([n][,opt]) - return or test an argument
BITAND(string1,string2[,pad])
BITOR (string1,string2[,pad]) - combine two strings with bit operations
BITXOR(string1,string2[,pad])
B2D(binary)
B2X(binary)
D2B(decimal)
C2X(string)
C2D(string[,n])
D2C(decimal[,n]) - convert between data formats
D2X(decimal[,n])
X2B(hex)
X2C(hex)
X2D(hex)
CENTER(s,n[,pad]) - centre a string in a field
CENTRE(s,n[,pad])
COMPARE(s1,s2[,pad]) - compare two strings
CONDITION([option]) - return information about trapped condition
Option can be (default I):
C (condition name) D (description)
I (instruction) S (status)
COPIES(s,n) - replicate a string
DATATYPE(string[,type]) - test datatype. Type can be:
A (alphanumeric) B (bits) L (lowercase)
M (mixed case) N (number) S (symbol chars)
U (upper case) W (whole number) X (hex)
DATE([format]) - get date. Format can be:
B (base date - days since 1/1/1 AD)
C (days in century) D (days in year)
E (European) J (Julian) M (month name)
N (normal: dd Mon yyyy) O (ordered)
S (sorted) U (USA) W (day of week)
DATE([format],date[,format]) - translate the given date from the latter
format to the former
DELSTR(string,n[,length]) - delete substring
DELWORD(string,n[,length]) - delete words
DIGITS() - NUMERIC DIGITS setting
ERRORTEXT(i) - Rexx error message
FORM() - NUMERIC FORM setting
FORMAT(number [,[before] [,[after] [,[expp] [,expt]]]] )
- format a number as specified
FUZZ() - NUMERIC FUZZ setting
INSERT(new,target[,[n][,[length][,pad]]]) - insert new string into target
JUSTIFY(s,n[,pad]) - justify text to given width
LASTPOS(needle,haystack[,start]) - find last occurrence of a string
LEFT(string,num[,pad]) - return an initial substring
LENGTH(string) - find the length of a string
LINESIZE() - find the terminal width
MAX(number[,number...]) - find the maximum of a set
MIN(number[,number...]) - find the minimum of a set
OVERLAY(new,target[,[n][,[length][,pad]]]) - overlay new string on to target
POS(needle,haystack[,start]) - find the first occurance of a string
QUEUED() - return the number of items on the stack
RANDOM([min][,[max][,seed]]) - return a random number
REVERSE(string) - find the reverse of a string
RIGHT(string,num[,pad]) - return a final substring
RXFUNCADD(rexxname,module,sysname) - load an external function
RXFUNCDROP(function) - drop an external function
RXFUNCQUERY(function) - query whether a function is loaded
SOURCELINE([i]) - return a line of the source program
SPACE(s[,[n][,pad]]) - evenly space words in a sentence
STRIP(string[,[opt][,char]]) - remove leading/trailing spaces
SUBSTR(string,n[,length[,pad]]) - return a substring
SUBWORD(string,n[,k]) - return a substring of words
SYMBOL(name) - test to see if a symbol is defined
TIME([format]) - get the time. Format can be:
C (civil time) N (normal) L (long)
H (hours since midnight)
M (minutes since midnight)
S (seconds since midnight)
O (offset from GMT) E (elapsed time)
R (elapsed time then reset)
TIME([format],time[,format]) - translate time from the latter format
to the former.
TRACE([setting]) - get and/or set trace mode (see trace
instruction)
TRANSLATE(string[,[tableo][,[tablei][,pad]]])
- translate characters using given tables
TRUNC(number[,n]) - truncate floating point number
VALUE(s[,[newvalue][,selector]]) - get or set value of a symbol
VERIFY(string,reference[,[option][,start]])
- verify string for valid characters
WORD(string,n) - return a word from a string
WORDINDEX(string,n) - return the position of a word in a string
WORDLENGTH(string,n) - return the length of a word in a string
WORDPOS(phrase,string[,start]) - find a phrase in a string
WORDS(string) - return the number of words in a string
XRANGE([a[,b]]) - return a range of characters
I/O functions (some of which are UNIX-specific)
CHARIN([stream] [,[position] [,count]]) - read characters
CHAROUT([stream] [,[string] [,position] ]- write characters
CHARS([stream]) - number of characters available
CLOSE(stream) - close a stream
FDOPEN(fd [,[mode] [,stream]]) - open an fd number
FILENO(stream) - find an fd number
FTELL(stream) - return the current file pointer
LINEIN([stream] [,[line] [,count]]) - read a line
LINEOUT([stream] [,[string] [,line]]) - write a line
LINES([stream]) - determine whether lines may be read
OPEN(file [,[mode] [,stream]]) - open a file
PCLOSE(stream) - close a pipe
POPEN(command [,[mode] [,stream]]) - open a pipe to a shell command
STREAM(stream [,[option] [,command]]) - miscellaneous stream operations
UNIX-specific functions
CHDIR(directory) - change to new directory
GETCWD() - return current working directory
GETENV(name) - get an environment variable
PUTENV(string) - set an environment variable
SYSTEM(s) - return the output of a shell command
USERID() - return the process owner's login name
Mathematical functions (implemented as separate package)
ACOS(x) the arc-cosine of x in radians (0<=acs(x)<=pi)
ASIN(x) the arc-sine of x in radians (-pi/2<=asn(x)<=pi/2)
ATAN(x) the arc-tangent of x in radians (-pi/2<=atn(x)<=pi/2)
COS(x) the cosine of x radians
EXP(x) the exponential of x (2.718281... to the power x)
LN(x) the natural logarithm of x (x>0)
SIN(x) the sine of x radians
SQRT(x) the square root of x (x>=0) [arbitrary precision possible]
TAN(x) the tangent of x radians (x <> pi/2)
TOPOWER(x,y) x to the power y