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
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votes
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SML/ML Int to String conversion
I have this code:
datatype 'a Tree = Empty | LEAF of 'a | NODE of ('a Tree) list;
val iL1a = LEAF 1;
val iL1b = LEAF 2;
val iL1c = LEAF 3;
val iL2a = NODE [iL1a, iL1b, iL1c];
val iL2b = NODE [iL1b, iL1c, iL1a];
val iL3 = NODE [iL2a, iL2b, iL1a,…
user494948
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2 answers
Standard ML permutations
I am working on a function to the permutations for all values in a list.
Here is what I have so far:
//MY ROTATE FUNCTION
fun rotate e [] = [[e]]
| rotate e (x::xs)= (e::x::xs)::(List.map (fn l => x::l) (rotate e xs));
//MY CURRENT PERMUTATION…
user494948
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1 answer
Write command-line arguments to file in SML
I am trying to write the command line arguments from my SML program into a file, each on a separate line. If I were to run sml main.sml a b c easy as 1 2 3 on the command line, the desired output would be to have a file with the…
Josue Espinosa
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Understanding an SML type fn (f,g,x) => g(f(x)) or similar
Ok, sorry in advance this probably is repost but I spent a good 30 minutes searching stackoverflow and couldn't find something similar enough to understand. Basically, I don't understand why
fn (f,g,x) => g(f(x))
gives the type
(’a -> ’b)*(’b ->…
user5510766
0
votes
1 answer
Multiplying list1 by list2, getting "Warning: match nonexhaustive"
From what I've learned,
fun addX (X, []) = []
| addX (X, y::ys) = (X + y :: addX(X, ys));
works perfectly fine, but when I try to multiply list1 by list2 with this method, it's giving me "Warning: match nonexhaustive", here's my code:
fun…
chenchen
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How to use number as Variable in following code?
I am very new to SML-NJ. I am writing a code to add the values of Number1 and Number2 in SML-NJ. I want to use the GRAAL like data type definition in my code.
Part - A :
type Variable=string
type Integer_constant=int
I want to do something like…
Bhushan Ladde
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2 answers
How to access a tuple of tuples in SML?
I have this:
val a = ((1,2),(1,2,1),(1,2,3),5,(4,5,6));
I need a function that returns few "x" is in this tuple...
Example:
Few "5" is in the tuple:
funMagic (a,5);
Must return 2
Help!
Neutron25
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- 1
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data constructor used without argument in pattern?
I'm not that familiar with SML but I have wrote the following program:
datatype 'a bin_tree = Leaf of 'a
| Node of 'a bin_tree * 'a bin_tree
fun height Leaf (x) = 0
| height Node (l1,l2) = 1 + Int.max(l1,l2)
fun is_balanced Leaf (x) = true
| …
charwayne
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1 answer
SML/NJ Error in Command Prompt
So I installed SML/NJ in Windows 10 using the Windows Installer Package "smlnj-110.79", and following the instructions in this coursera video lecture, i should be able to open the command prompt and access sml by typing "sml". However, when I return…
A. Chiasson
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how to stop a recursive function in this case (SML)
fun p(L) =
[L] @ p( tl(L) @ [hd(L)] );
If L is [1,2,3] then I want to have a [ [1,2,3], [2,3,1], [3,1,2] ].
Since every time I append the first num to the end, then if L = [] then [] doesn't work here.
How to stop the function once it has the…
Jam
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votes
1 answer
SMLNJ expand # in output
I have the following:
val it = DATAX ("hello",DATAX ("world",DATAX #,DATAX #),...
Is there a way to make the SMLNJ interpreter expand "#" so that I can see what the exact data is? Thanks!
minghan
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variable gets forgotten after print statement
Why does this compile?
fun foo (h::t) =
h = hd(t);
But this does not
fun foo (h::t) =
PolyML.print (h::t);
print "\n";
h = hd(t);
?
Value or constructor (h) has not been declared Found near =( h, hd(t))
Value or constructor (t)…
lo tolmencre
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0
votes
1 answer
print statement causing error?
The syntax in this language is confusing.
fun bar a =
print (Int.toString a);
0
compiles. No idea why emacs indents the 0 though.
fun bar a =
print (Int.toString a)
0
Throws an error.
Error: operator is not a function [tycon mismatch]
…
lo tolmencre
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Editing tuples in a list of sml
I want to make a list which is of specification :(string*int) list and the tuples can be edited. For example, suppose
val gamma = [("a",20),("b",30),("c",40)] :(string*int) list
Now, how can I change the value 30 in the tuple ("b",30) to , let's…
Ankit Shubham
- 2,989
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Can you formulate a case expression in a function that will accept the datatype cards and will return a boolean?
datatype cards = king of int * int
| queen of string
| jack of cards
| ace of cards * cards
| joker of int * cards
Ronchi Floyd
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