Error Messages

Contents

• Compiler Errors
• Compiler Warnings
• Run Time Errors
• Run Time Warnings

Compiler Errors

parse error

Syntax Error. Cause of this error can be Type Mismatch, missing of period in type definitions etc.

Trace function called to non-predicate type [type]

trace/1 is used for a non-predicate type. This can result in undefined type Warning, if there is a typo.

Type '[type1]' and '[type2]' makes a loop in the type hierarchy

When the type hierarchy makes a loop e.g., trying to set a <- a will result in this error.

Type '[type1]' and '[type2]' have two MGSATs, '[type3]' and '[type4]'

See  type unification for details.

Feature '[feature]' is defined twice

Feature having same name is defined more than twice.

Type '[type]' is defined twice

Type having same name is defined more than twice.

Cannot generate a feature structure

Due to fatal error, the feature structure cannot be generated. Normally gets resolved when other errors are fixed.

Unknown feature name: '[feature]'

Trying to use unknown feature name.

Feature '[feature]' is restricted to '[type1]', and cannot take '[type2]'

Predicate '[type]' cannot take [num]-arity

Mismatch in number of arguments

Cannot unify these two TFSs
Cannot unify: [type1] & [type2]

Unification errors due to type mismatch.

Argument list length over [MAXNUM]

The maximum number of arguments has been exceeded.

Tail of a list is restricted to 'list', and cannot take '[type]'

Unlike LISP,  Tail of list 'tl\' can only take a list (or 'cons', 'nil')

Type [type] is not a subtype of 'pred' but used as a predicate

Redefine pred as subtype

Built-in procedure '[type]' cannot be redefined

Built-in procedure with same name as type cannot be defined or used.

Built-in procedure '[type]' cannot be traced

Cannot trace built-in functions

Input is neither type declaration nor clause definition

Not a parse error. Syntax error

Compiler Warnings

Feature definition form 'FEAT(pr):type' is obsolete; use new form 'FEAT:type(pr)'

Feature definition form is obsolete. Use New Form.

Type '[type]' is undefined; treated as a subtype of 'bot'

Undefined type. Please define type before using it.

Type '[feature]' is undefined; treated as a subtype of 'feature'

Undefined Feature . Please define feature before using it.

Type '[pred]' is undefined; treated as a subtype of 'pred'

Undefined Predicate. Please define Predicate before using it.

Singleton Variable '[variable]'

Variable is used only once. Use bot instead.

Run Time Errors

include/1 requires a file name

'include/1' does not contain a valid string. please specify file name as 'string'.

Cannot open include file: '[filename]'

Cannot open the file for reading. Please check for existence and validity of the file.

read_lilfes/3 requires a file name

First parameter has to be a valid file name in 'string' format.

Cannot open read file: '[filename]'

Cannot open the file for reading. Please check for existence and validity of the file.

read_lilfes_with_prefix/3 requires a file name

First parameter has to be a valid file name in 'string' format.

switch_output_to_file/1 requires a file name

First parameter has to be a valid file name in 'string' format.

switch_output_to_file/1 cannot open file '[filename]'

Cannot open the file for reading. Please check for existence and validity of the file.

switch_output_to_file_append/1 requires a file name

First parameter has to be a valid file name in 'string' format.

switch_output_to_file_append/1 cannot open file '[filename]'

Cannot open the file for writing. Please check for existence and validity of the file.

assert/1 cannot take a query

Query cannot be asserted.

asserta/1 cannot take a query

Query cannot be asserted.

value_intval requires an integer in setting an array

value_string requires a string in seting an array

Error: both ARRAY_BASE and ARRAY_SIZE must be specified for key_integer

Error: ARRAY_SIZE must be integer

Error:: predicate set_array/1 can be used to only declare_array'ed predicate

Error: Predicate follow/3 requires feature in the 2nd argument

Normally missing of "\", can result in this error.

Run Time Warnings

Non-integer cannot use as a key of an integer array

Argument has to be integer

Integer out of array-range

Out of array range index is used

Non-string cannot use as a key of a string hash

Argument has to be string

Non-integer cannot use as a key of an integer hash

Argument has to be integer

Warning: Predicate follow/3 requires feature in the 2nd argument

Normally missing of "\", can result in this error.

Warning: Predicate restriction/2 requires feature in the 2nd argument

Normally missing of "\", can result in this error.

strtotype/2 requires a string Warning: strtotype/2 requires a string

Argument has to be string

Warning: listtostr requires a list

Argument has to be list of integers

Warning: listtostr requires a list of integer

Argument has to be list of integers

Warning: strprint/1 requires a string

Argument is not string.

Warning: strprintln/1 requires a string

Argument is not string.