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
SOME([]) interpreted as 'z -> 'z option rather then 'z list option
Hi im trying to write a simple function using the standard library
it should take the following argument
try = fn: 'a -> 'b list option
a_list = 'a list
and the defintion is the following:
fun all_answers try a_list =
let fun acc(SOME(a),…
user25470
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votes
2 answers
How to shorten a list in standard ml
I just start working with standard ml and really have some trouble understanding the list in this language. So my question is how to shorten a list in ml ? For example, if I have a list [1,2,3,4,5,6], I want to shorten it to [1,2]. What I'm having…
user4075830
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votes
2 answers
Change a variable in standard ml list
I wonder when working with list in ml, how to change a variable with specific location of the list. For instance, when I have a list [1,2,3,4], I want to change the list to [1,2,5,4] with the 5 subtitle for the 3. What i'm thinking is to write a…
user4075830
- 87
- 1
- 2
- 11
0
votes
2 answers
How to calculate indegree and outdegree for a graph in directed graph SML code?
I have a tuple like (1,2),(3,4),(4,5). Edges: 1->2, 3->4 and so on.
How calculate in degree and out degree for each vertex?
offeron
- 157
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votes
2 answers
Differentiate between atom and list in SML
I am new to SML programming and I have a problem to create a function to remove occurrences of an atom A from a list of integers. This list can be nested to any levels,
means we can have list like [1,2,3] and we can have list like [[1,2],[2,3]] as…
0
votes
1 answer
2D Binary Tree in SML
I am having a difficult time figuring out how to implement a 2d binary tree using sml
This is what I have so far but I get a tycon mismatch.
datatype btree =
Empty |
Node of int * btree * btree;
fun AddNode…
UnhinderedLimpidity
- 29
- 6
0
votes
2 answers
Checking for matching parenthesis
I am trying to write a code such that, given a list of parenthesis, I will check if the order is valid or not.
For simpleness, the follwoing datatype is defined.
datatype par = LPAR | RPAR
type pList = par list
What I have until now is:
fun…
Sarah cartenz
- 1,313
- 2
- 14
- 37
0
votes
2 answers
NLFFI: wrong values are sent to C function arguments of type "short"
It seems like a bug in NLFFI SML/NJ implementation. C function is
void f0
( short a0
, short a1
and so on
, short a7
) {
printf ("a0 == %hx\n", a0);
printf ("a1 == %hx\n", a1);
and so on
printf ("a7 == %hx\n", a7);
}
I…
beroal
- 369
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- 14
0
votes
1 answer
Datatype for Dijkstra's algorithm?
I'd like to turn a 2D array (having nodes but also obstacles) into a graph in order to run Dijkstra's algorithm in SML, but as a beginner I don't come up with a good idea about the datatype I should use.
Any help is welcome, thanks.
luthien
- 1,285
- 3
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- 26
0
votes
1 answer
SML/NJ Read next character from file ignoring whitespace
Can you give me a solution to create a function that reads the next character in a file stream, ignoring whitespace? (in SML/NJ).
Noob Doob
- 1,757
- 3
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- 27
0
votes
1 answer
Function binding and function call evaluation
I have a little trouble understanding the evaluation of function bindings and function calls in SML.
A simple example of a function binding and a function call:
val w = 12;
fun pow(x:int,n:int) =
if n = 0
then 1
else x *…
TheAptKid
- 1,559
- 3
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- 47
0
votes
1 answer
Evaluate or execute a string in sml
I'm looking for a way to execute as string in sml. For example:
val evalResult = eval "1 + 1";
> val it = 2 : int
I can't actual believe that I didn't find any resource on this topic...
Any help is appreciated.
scheffield
- 6,618
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votes
1 answer
How do I open and run ML Lex on Windows 7?
I downloaded the SMLNJ installer for Windows and ran it. This has created a shortcut to SML of New Jersey which I can use as an ML interpreter. This installer is also supposed to have installed ML Lex, but I have absolutely no idea about how to run…
James Wright
- 119
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votes
1 answer
What's "node" doing in this snippet of SML?
I'm working on a project that has a lot code that looks like this:
structure MyStruct = struct
datatype node
= A of Foo.t
| B
type t = node Wrap.t
fun layout myNode =
case node myNode of
A foo => Foo.bar foo
| B => "void"
end
Wrap is…
Patrick Collins
- 10,306
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- 69
0
votes
1 answer
Trying to understand the Lex syntax for Standard ML (ml-lex)
I'm writing a compiler. I'm at the first phase, trying to tokenize everything. I wrote it all up, but I get an error. I've read the docs (smlnj) three or four times, and the errors are not very informative.
I think I must be messing up the state…
robins35
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