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Chapter 9 : SYSTEM MESSAGES
This chapter lists all messages displayed by SNOBOL4.
When SNOBOL4 begins execution, this title is displayed:
Vanilla SNOBOL4 Version 2.14.
(c) Copyright 1984,1988 Catspaw, Inc. All Rights Reserved.
Additional messages which may appear:
Termination messages are normally produced on I/O unit 7, which
defaults to the user's display screen. If the /B option was used
in the invoking command line, they are produced on I/O unit 6,
associated with variable OUTPUT. Dump messages are always produced
to unit 6.
- Cannot open file: name
The file specified in the command line cannot be opened.
- Command line error:
A syntactic error was detected in the SNOBOL4 command line. The
command line is displayed on two lines. The line break shows
where the error occurred.
- Errors detected in source program
There were compilation errors in the source program. Execution
will proceed until a statement with a compilation error is
- Insufficient storage for initialization
Not enough memory was available to initialize the SNOBOL4 system.
- No errors
Compilation is complete, and without error. Execution begins
- Normal termination at level LL
The program transferred to the label END. LL is the current
program-defined function call depth. This message is produced
only if the /S command line option (statistics) was used.
- filename(XXX) : Last statement executed was NNN
NNN is the statement number of the last statement executed, XXX
is its source line number. It is the statement that transferred
to the END statement. If this was a normal termination, it is
only displayed if the /S option was used.
- filename(XXX) : Warning: Interrupted in statement NNN at level LL
Execution was interrupted when you pressed the BREAK or control-C
key. The interruption occurred before the specified statement
was executed. LL is the current call depth of program-defined
- Incomplete storage regeneration. Terminal dump not possible
Stack overflow occurred during storage regeneration, and the
&DUMP keyword was nonzero. Memory is in an indeterminate form,
and a dump listing cannot be produced.
- Dump of variables at termination
These headings will appear if a termination dump was requested by
setting the &DUMP keyword nonzero. Variables are listed only if
they contain a nonnull value. The variable names will be sorted
if the &DUMP keyword is positive; they are unsorted if it is
9.2.1 Job Statistics
End-of-run statistics on program execution are provided if the
/S command line option is used. Compilation and execution times
are in tenths of a second. Times are wall-clock values, and
include all I/O wait time, such as delays for keyboard input:
SNOBOL4 statistics summaryNN
tenths of a second compilation time
NN tenths of a second execution time
NN statements executed, NN failed
NN arithmetic operations performed
NN pattern matches performed
NN regenerations of dynamic storage
NN reads performed
NN writes performed
SNOBOL4 syntax errors are detected during compilation. Statement
compilation ceases at the point where the error was detected.
The error message contains a marker which indicates the
valid portion of the statement accepted by the compiler---the
error occurred after this point. Only the first error in a
statement is detected. The erroneous statement is compiled with
an internal error code which produces an error message if the
statement is executed. Compilation resumes with the next statement.
Compilation ceases and SNOBOL4 terminates if more than 50
errors are found.
When compiling without a list file (/L: command line option),
the compiler will attempt to display the erroneous line on your
screen. If a statement is continued over several lines, only the
line in error is displayed. Several errors cannot be detected
until the absolute end-of-statement is found. This may require
reading the next line, and finding it is NOT a continuation
statement. In this case, the single line displayed will be the
NEXT line, with the error marker in the first character position.
The CODE function may be used to compile SNOBOL4 statements
that have been concatenated into a long string. The CODE function
fails if a syntax error is found, and the keyword &ERRTEXT
contains the error message string for the error encountered.
Most program logic errors can only be detected during program
execution. Some are unconditionally fatal, and cause the SNOBOL4
system to terminate. Others are conditionally fatal---the system
terminates if the value of the keyword &ERRLIMIT is zero. If
&ERRLIMIT is nonzero, the keyword &ERRTYPE is set to the error
message number, &ERRTEXT is set to the message text, &ERRLIMIT is
decremented, and execution continues.
- Binary operators must be surrounded by blanks
Omitting a blank will often cause this error. An illegal or
undefined binary operator will also produce this error.
- Error in GOTO
There is a syntactic error in the GOTO field.
- Erroneous END statement
The END statement contains a syntactic error, or the label specified
in the subject field for initial transfer could not be
- Erroneous integer
An integer number appears which is too large for the SNOBOL4 system.
The allowable range for magnitude values is 0 to 32767.
- Erroneous label
The first character of a statement must be blank, tab, alphanumeric,
* (comment), + or . (continuation), or - (control).
- Erroneous or missing break character
A character which separates language elements occurs in an illegal
context, or an expression is not balanced with respect to
- Erroneous subject
A compiler break character appears before the statement subject
field. The break characters are comma, equal sign, right parenthesis,
right square bracket (]), and right angular bracket (>).
- Illegal character in element
A character was found which was incorrect for the type of language
object being compiled. This often occurs when a blank is
omitted between elements, causing them to run together.
- Improperly terminated statement
The source statement terminated with an incomplete language construction.
- Limit on compilation errors exceeded
More than 50 compilation errors were found in the source program.
- No END statement in source file
End-of-File was encountered in the source file without an END
- Previously defined label
A duplicate label appears. The first definition is retained;
subsequent definitions are discarded.
- Unclosed literal
The closing quotation mark from a literal string is missing.
This error also occurs if the closing quotation mark (single or
double) was different from the opening mark.
The protected keyword &ERRTYPE may be traced, permitting a
program-defined function to gain control when a conditional error
occurs. THe program CODE.SNO provides an example of how to do
this. The initial value of the unprotected keyword &ERRLIMIT is
zero, forcing program termination upon any error.
Errors 1-16 are conditionally fatal. Errors 17-28 are unconditionally
fatal. When execution terminates due to an error, the
following is displayed:
filename(XXX) : Error NN, -- description --
In statement NNN, at level LL
NN is the error number below. NNN is the statement number
assigned in the compiler list file, XXX is the absolute line
number in the source file. LL specifies the current programdefined
function call depth (0 is the normal main-program level).
Tracing is provided for variables, certain keywords, label
transfers, and function calls and returns. A trace message is
output to I/O unit 6 for each trace occurrence. Program execution
time, in tenths of a second, is appended to each message.
- 1. Illegal data type
The data type of an operand was incorrect for the type of operation
attempted. This occurs most frequently with arithmetic operations,
when one operand is a string which cannot be converted
to a number.
- 2. Error in arithmetic operation
An arithmetic operation upon integer values produced a result
which was out of range, or was undefined, such as division by
- 3. Erroneous array or table reference
An array or table reference was made to a variable which did not
contain an array or table pointer.
- 4. Null string in illegal context
The null string appeared where it is not permitted, such as the
object of an indirect reference.
- 5. Undefined function or operation
A function was called before it was defined, or an undefined
operator was used.
- 6. Erroneous prototype
A syntactic error occurred in the prototype string used with the
functions ARRAY, DATA or DEFINE. Note that the blank and tab
characters are not permitted within the prototype string.
- 7. Unknown keyword
The keyword specified is unknown to the SNOBOL4 system.
- 8. Variable not present where required
A variable name must be used as the subject of an assignment
statement, or as the argument of the unary cursor, name, or keyword
operator (@, ., &), or the binary pattern match assignment
operators (., $).
- 9. Entry point of function not label
At the time a program-defined function was first called, its
entry point label did not appear as the label of any SNOBOL4
- 10. Illegal argument to primitive function
An illegal value was used as an argument to the function ARG,
FIELD, LOCAL, OPSYN, STOPTR, or TRACE, or an illegal value was
specified in the third argument to INPUT or OUTPUT.
- 11. Reading error
An error condition was returned when reading from a file.
- 12. Illegal I/O unit
Allowable unit numbers are 1 through 16 (inclusive). (Unit 0 is
allowed in functions INPUT and OUTPUT, and is converted to units
5 and 6 respectively.)
- 13. Limit on defined data types exceeded
SNOBOL4 allows 899 different program-defined data types.
- 14. Negative number in illegal context
A negative number was used incorrectly as the argument of the
function LEN, POS, TAB, or RTAB.
- 15. String overflow
The program attempted to create a string larger than &MAXLNGTH
- 16. Overflow during pattern matching
The internal SNOBOL4 stack overflowed during pattern matching.
This can happen when a recursive or looping pattern is incorrectly
- 17. Error in SNOBOL4 system
This message indicates an internal SNOBOL4 system error.
- 18. Return from level zero
An attempt was made to transfer to the function return label
RETURN, FRETURN, or NRETURN outside of any function call.
- 19. Failure during GOTO evaluation
The expression used for an indirect transfer within the GOTO
field failed when evaluated.
- 20. Insufficient storage to continue
All available memory has been used. Vanilla SNOBOL4 is limited
to 30K bytes for program and data. SNOBOL4+, Catspaw's enhanced
version, allocates 300K bytes for program and data.
- 21. Stack overflow
The SNOBOL4 internal stack has overflowed. This may be caused by
excessive function recursion, or occur during memory garbage
- 22. Limit on statement execution exceeded
The number of statements executed was greater than the value in
the keyword &STLIMIT. &STLIMIT is initially -1, specifying
- 23. Object exceeds size limit
The program attempted to create an object larger than the maximum
- 24. Undefined or erroneous GOTO
A transfer was attempted to an undefined label, or an expression
in a GOTO field evaluated to a string, rather than a label
name---usually the result of omitting the indirect operator ($).
- 25. Incorrect number of arguments
A primitive function was called with too many arguments.
- 28. Execution of statement with compilation error
Execution proceeded to a statement that contained a compilation
- Tracing normally occurs only if the keyword &TRACE is nonzero.
However, another keyword, &FTRACE, may be set nonzero to trace
all function calls and returns independently of keyword &TRACE.
- STATEMENT NN: <vname> = <value>,TIME = TT
Value trace; produced by the function call TRACE('vname',
'VALUE'), where vname is the name of the variable to be traced.
- STATEMENT NN: &<keyname> = <value>,TIME = TT
Keyword trace; produced by the function call TRACE('keyname',
'KEYWORD'), where keyname is the upper case keyword name, without
the leading ampersand.
- STATEMENT NN: TRANSFER TO <labname>,TIME = TT
Label trace; produced by the function call TRACE('labname',
'LABEL'), where labname is the desired label name. Tracing only
occurs on a transfer of control; it does not occur if the labeled
statement is flowed into.
- STATEMENT NN: LEVEL LL CALL OF <fname>(arg1,...,argn),TIME = TT
Call trace; produced by the function call TRACE('fname', 'CALL'),
where fname is the name of the function to be traced. The function's
arguments at the time of the call are evaluated and displayed.
- STATEMENT NN: LEVEL LL RETURN OF <fname> = <value>,TIME = TT
STATEMENT NN: LEVEL LL NRETURN OF <fname> = <value>,TIME = TT
STATEMENT NN: LEVEL LL FRETURN OF <fname>,TIME = TT
Return trace; produced by the function call TRACE('fname',
'RETURN'), where fname is the name of the function whose return
is to be traced. The type of return that occurred is displayed
in the trace message.
- ***Print request too long***
An internal buffer is used to display trace messages, and variable
values during dumps. If the required display is longer than
1,800 characters, this error message is produced instead.
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