Prolog - 'unknown clause' error message when asking for user input when using PIE (Prolog Interface Engine)
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I'm writing code for a simple program that outputs any phrase that the user inputs. Here's my code so far:
input():-
read(X),
nl,
write(X).
Here's the output:
input().
input().
Unknown clause found read(X$0)
Execution terminated
No solutions
Here's my desired output:
input().
input().
hello
hello
prolog
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
add a comment |
I'm writing code for a simple program that outputs any phrase that the user inputs. Here's my code so far:
input():-
read(X),
nl,
write(X).
Here's the output:
input().
input().
Unknown clause found read(X$0)
Execution terminated
No solutions
Here's my desired output:
input().
input().
hello
hello
prolog
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
add a comment |
I'm writing code for a simple program that outputs any phrase that the user inputs. Here's my code so far:
input():-
read(X),
nl,
write(X).
Here's the output:
input().
input().
Unknown clause found read(X$0)
Execution terminated
No solutions
Here's my desired output:
input().
input().
hello
hello
prolog
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
I'm writing code for a simple program that outputs any phrase that the user inputs. Here's my code so far:
input():-
read(X),
nl,
write(X).
Here's the output:
input().
input().
Unknown clause found read(X$0)
Execution terminated
No solutions
Here's my desired output:
input().
input().
hello
hello
prolog
prolog
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
edited Nov 23 '18 at 13:59
Guy Coder
16.3k44287
16.3k44287
asked Nov 23 '18 at 12:49
plants thoplants tho
132
asked Nov 23 '18 at 12:49
plants thoplants tho
132
asked Nov 23 '18 at 12:49
plants thoplants tho
132
132
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Note: In a comment the OP noted this was originally done using PIE (Prolog Interface Engine)
Your problem is that you are using read/1 which expects a Prolog term. Prolog terms are not strings that can be of any form, Prolog terms end with a period (.). So in your example input(). works because it ends with a period, hello does not work because it does not end with a period.
Using your query
?- input().
|: input().
and entering input(). works
input()
true.
?- input().
|: hello
|: .
entering hello does not work right away as indicated by the second prompt |: but then entering the . completes the Prolog term and works.
hello
true.
--
Here is demo of your code, slightly modified running on SWISH.
When I ran your code with SWI-Prolog installed on my laptop it worked with input() as the predicate. When I tried the same with SWISH it complained, but changing the predicate from input() to input solved that problem.
Now knowing that you are not using a common Prolog such as SWI-Prolog and seeing the error message
Unknown clause found read(X$0)
tells me that PIE does not have read/1, I did a quick check of some tutorials for PIE and could not find any use of read/1. The obvious conclusion is that PIE does not support read/1 and if you want to use read/1 while learning Prolog you will have to use something that does, e.g. SWI-Prolog, SWISH, GNU Prolog
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
The thing is: it doesn't allow me to enter an input. When I call theinput()method, it is supposed to allow me to enter something but when I typeinput().and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps
– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -SWISH: SWI-Prolog for SHaringIt runs in a browser.
– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
add a comment |
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1 Answer
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1 Answer
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active
oldest
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Note: In a comment the OP noted this was originally done using PIE (Prolog Interface Engine)
Your problem is that you are using read/1 which expects a Prolog term. Prolog terms are not strings that can be of any form, Prolog terms end with a period (.). So in your example input(). works because it ends with a period, hello does not work because it does not end with a period.
Using your query
?- input().
|: input().
and entering input(). works
input()
true.
?- input().
|: hello
|: .
entering hello does not work right away as indicated by the second prompt |: but then entering the . completes the Prolog term and works.
hello
true.
--
Here is demo of your code, slightly modified running on SWISH.
When I ran your code with SWI-Prolog installed on my laptop it worked with input() as the predicate. When I tried the same with SWISH it complained, but changing the predicate from input() to input solved that problem.
Now knowing that you are not using a common Prolog such as SWI-Prolog and seeing the error message
Unknown clause found read(X$0)
tells me that PIE does not have read/1, I did a quick check of some tutorials for PIE and could not find any use of read/1. The obvious conclusion is that PIE does not support read/1 and if you want to use read/1 while learning Prolog you will have to use something that does, e.g. SWI-Prolog, SWISH, GNU Prolog
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
The thing is: it doesn't allow me to enter an input. When I call theinput()method, it is supposed to allow me to enter something but when I typeinput().and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps
– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -SWISH: SWI-Prolog for SHaringIt runs in a browser.
– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
add a comment |
Note: In a comment the OP noted this was originally done using PIE (Prolog Interface Engine)
Your problem is that you are using read/1 which expects a Prolog term. Prolog terms are not strings that can be of any form, Prolog terms end with a period (.). So in your example input(). works because it ends with a period, hello does not work because it does not end with a period.
Using your query
?- input().
|: input().
and entering input(). works
input()
true.
?- input().
|: hello
|: .
entering hello does not work right away as indicated by the second prompt |: but then entering the . completes the Prolog term and works.
hello
true.
--
Here is demo of your code, slightly modified running on SWISH.
When I ran your code with SWI-Prolog installed on my laptop it worked with input() as the predicate. When I tried the same with SWISH it complained, but changing the predicate from input() to input solved that problem.
Now knowing that you are not using a common Prolog such as SWI-Prolog and seeing the error message
Unknown clause found read(X$0)
tells me that PIE does not have read/1, I did a quick check of some tutorials for PIE and could not find any use of read/1. The obvious conclusion is that PIE does not support read/1 and if you want to use read/1 while learning Prolog you will have to use something that does, e.g. SWI-Prolog, SWISH, GNU Prolog
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
The thing is: it doesn't allow me to enter an input. When I call theinput()method, it is supposed to allow me to enter something but when I typeinput().and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps
– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -SWISH: SWI-Prolog for SHaringIt runs in a browser.
– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
add a comment |
Note: In a comment the OP noted this was originally done using PIE (Prolog Interface Engine)
Your problem is that you are using read/1 which expects a Prolog term. Prolog terms are not strings that can be of any form, Prolog terms end with a period (.). So in your example input(). works because it ends with a period, hello does not work because it does not end with a period.
Using your query
?- input().
|: input().
and entering input(). works
input()
true.
?- input().
|: hello
|: .
entering hello does not work right away as indicated by the second prompt |: but then entering the . completes the Prolog term and works.
hello
true.
--
Here is demo of your code, slightly modified running on SWISH.
When I ran your code with SWI-Prolog installed on my laptop it worked with input() as the predicate. When I tried the same with SWISH it complained, but changing the predicate from input() to input solved that problem.
Now knowing that you are not using a common Prolog such as SWI-Prolog and seeing the error message
Unknown clause found read(X$0)
tells me that PIE does not have read/1, I did a quick check of some tutorials for PIE and could not find any use of read/1. The obvious conclusion is that PIE does not support read/1 and if you want to use read/1 while learning Prolog you will have to use something that does, e.g. SWI-Prolog, SWISH, GNU Prolog
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
Note: In a comment the OP noted this was originally done using PIE (Prolog Interface Engine)
Your problem is that you are using read/1 which expects a Prolog term. Prolog terms are not strings that can be of any form, Prolog terms end with a period (.). So in your example input(). works because it ends with a period, hello does not work because it does not end with a period.
Using your query
?- input().
|: input().
and entering input(). works
input()
true.
?- input().
|: hello
|: .
entering hello does not work right away as indicated by the second prompt |: but then entering the . completes the Prolog term and works.
hello
true.
--
Here is demo of your code, slightly modified running on SWISH.
When I ran your code with SWI-Prolog installed on my laptop it worked with input() as the predicate. When I tried the same with SWISH it complained, but changing the predicate from input() to input solved that problem.
Now knowing that you are not using a common Prolog such as SWI-Prolog and seeing the error message
Unknown clause found read(X$0)
tells me that PIE does not have read/1, I did a quick check of some tutorials for PIE and could not find any use of read/1. The obvious conclusion is that PIE does not support read/1 and if you want to use read/1 while learning Prolog you will have to use something that does, e.g. SWI-Prolog, SWISH, GNU Prolog
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
edited Nov 23 '18 at 13:44
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
answered Nov 23 '18 at 13:04
Guy CoderGuy Coder
16.3k44287
16.3k44287
The thing is: it doesn't allow me to enter an input. When I call theinput()method, it is supposed to allow me to enter something but when I typeinput().and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps
– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -SWISH: SWI-Prolog for SHaringIt runs in a browser.
– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
add a comment |
The thing is: it doesn't allow me to enter an input. When I call theinput()method, it is supposed to allow me to enter something but when I typeinput().and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps
– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -SWISH: SWI-Prolog for SHaringIt runs in a browser.
– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
The thing is: it doesn't allow me to enter an input. When I call the
input() method, it is supposed to allow me to enter something but when I type input(). and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps– plants tho
Nov 23 '18 at 13:08
The thing is: it doesn't allow me to enter an input. When I call the
input() method, it is supposed to allow me to enter something but when I type input(). and hit enter, it shows up the unknown clause error message above. I'm running this on PIE (Prolog Interface Engine) if that helps– plants tho
Nov 23 '18 at 13:08
If you don't want to download and install Prolog then try SWISH -
SWISH: SWI-Prolog for SHaring It runs in a browser.– Guy Coder
Nov 23 '18 at 13:13
If you don't want to download and install Prolog then try SWISH -
SWISH: SWI-Prolog for SHaring It runs in a browser.– Guy Coder
Nov 23 '18 at 13:13
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
works like a charm on swish but gives me trouble on PIE. I guess the issue here is PIE not my code. Thank you so much!!!!
– plants tho
Nov 23 '18 at 13:29
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
won't let me upvote because I don't have enough reputation points :(
– plants tho
Nov 23 '18 at 13:39
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
@plantstho I lose more points because of that silly requirement. Thanks. I should send the bill to SO for those.
– Guy Coder
Nov 23 '18 at 13:41
add a comment |
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