Standard ML of New Jersey (SML/NJ)
SML/NJ is a popular implementation of the Standard ML programming language that was co-developed jointly by Bell Laboratories and Princeton University. It is released under a BSD like license.
References:
Questions tagged [smlnj]
866 questions
0
votes
1 answer
Tail recursion in SML does not present any output
Following my previous post here , I tried to do what was suggested and convert the code
into a Tail-recursion method with let .
The original code - which does not work (due to using val inside if condition) :
fun func() =
val decimal = 0 (* the…
JAN
- 21,236
- 66
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votes
4 answers
how to run sml/nj program under emacs
after one day struggle I finally configure Emacs for SML/NJ.
I am new to both emacs and SML, now I am having problem to how to run sml program under emacs.
when I command,
M-x sml-mode
it looks OK, no error report.
and after open(or create file…
user1869952
0
votes
2 answers
Recognition of data type in SML
This is confusing but working code. I just want some help in understanding why k::ks is taken as a'list list list and not a'list list.
I want to take a list and a list of lists and check whether the first list is necessary.
By necessary I mean,…
user1709828
0
votes
1 answer
Where am I going wrong with this code?
I am trying to calculate the sum of the squares of the first n numbers. Here is the code:
fun sumSq 0 = 0 |
sumSq x = x + sumSq(x * x-1);
I am getting an uncaught exception Overflow[overflow] error.
Graeme
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- 2
0
votes
1 answer
Print error in SML because of types mismatch
I' trying to print a types value in SML and with no success.
Please take a look at the code below and let me know what do I need to do in order to fix this.
Thanks.
(* Language Definition *)
datatype = Id of string;
(* Expression Definition…
Alexander Tilkin
- 149
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0
votes
1 answer
Assigning values to a list of variables
I want to input two lists of equal length and assign the values of one list to variables of another.
I want it to realize first list automatically as list of variables and second as values.
e.g.
I want to assign [1,2,3,4,5,6] values to the elements…
700resu
- 259
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0
votes
1 answer
Count number of occurances of an element in a list
I have the following function:
getcountof(x,l::ls) =
if x=l then (1 + getcountof(x,ls))
else getcountof(x,ls)
|getcountof(x,[]) = 0;
Can someone tell me whats wrong in it?
I get the error:
stdIn:1.2-1.17 Error: syntax error: deleting ELSE…
Rpant
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0
votes
2 answers
How do I make a function that writes data into a file give boolean output?
I have to write a code that takes integer list and writes them to a file. At the same time it returns true if the element is written, else false if it is not written.
I wrote something like
fun writetofile([],sfile)= false
|writetofile((l:int)::ls,…
700resu
- 259
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- 16
0
votes
1 answer
withtype fails with mlton and succeeds with smlnj
I am writing an application where I want to define many types in the withtype clause of a datatype declaration. The following code snippet demonstrates it:
datatype ta = A
withtype tb = int
and tc = tb
mlton fails to compile this code,…
Romildo
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0
votes
1 answer
writing integers to a file in sml
Is there a output in textIO signature to write integers to a file? output only writes vectors, outputsstring writes substrings and output1 writes only characters. My problem with not using vectors is I have to write each integer into a line in the…
700resu
- 259
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- 16
0
votes
1 answer
Is there a inbuilt function to check if a number is integer in SML
Is there an inbuilt is integer function in sml?
I mean something like:
I have to read a number from file and display it as output if it integer and raise exception if the number is not integer. for example I have to check if the output of…
700resu
- 259
- 6
- 16
0
votes
2 answers
How to exit a function without returning a value
Suppose I have a function that returns a certain value when it satisfies a given condition and does not return any value when the condition is not satisfied.
e.g.
fun foo(n)= if n< 100000 then n else (something like exit function. We have it in…
700resu
- 259
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0
votes
1 answer
Understanding Text IO
My function is trying to read a textfile line by line and carry out a certain predefined function on each line called somefn and append the value of somefn to the function. The somefn is already defined above this and works fine.
fun…
700resu
- 259
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- 16
0
votes
1 answer
Raising IO Exceptions in SML
Exception IO has structure:
Exception IO of {
name: string
....
...}
some other arguments that I do not understand.
Do I have to assign all these. I mean what do I do after this?
exception IO of {inputfile}
I usually define exception and then…
700resu
- 259
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- 16
0
votes
1 answer
Output and Input in SML
I am trying to understand TextIO to write and read files line by line. Most resources online start without some introductory texts. I do not have any previous knowledge with file handling and no advanced knowledge with SML. I do not know how to deal…
700resu
- 259
- 6
- 16