Questions tagged [programming-languages]
Questions related to design, implementation, and analysis of programming languages. NOT for questions about how to program, which are off-topic on this site.
-2
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0answers
17 views
Visual Basic Tax Calculator project [on hold]
For my first project in my CS class I have to make a "simple" tax calculator but I can't even start it.
For your first project you are to create a tax calculator. You are to build your program, input ...
-1
votes
0answers
13 views
visual basic displaying in different forms by module [closed]
How can I display MICROSOFT ACCESS data ( supplier) from datagridview1 of different form by calling it from the module? is it possible?
i have tried to display it using private sub but i want my ...
1
vote
0answers
25 views
Reasons for why x - 1 and x -1 gives different result in F# [closed]
I assume the reason space makes a difference in F# is due to reserving a certain function, when minus is in front of a number without space, however what are the reasons for this? I can't seem to find ...
2
votes
3answers
78 views
How does a computer “wait” time?
Me and a friend were discussing how programming languages can perform asynchronous tasks, like waiting 15 seconds before performing another task, and we started a debate.
I know that computers have ...
4
votes
1answer
45 views
Type system and language that implements type constraints?
Occasionally when writing programs in a statically typed language, e.g. some ML, I find having to write code for cases I know will not happen. This is because I know e.g. that a function on some data-...
1
vote
0answers
19 views
Converting (reverse-engineering) Turing machine into program or most concise algorithm?
It is known that every program or every algorithm can be converted to Turing machine. But what about the reverse process? Is there algorithm (or research trend that considers such algorithm) to ...
39
votes
2answers
7k views
How does Tarjan's pseudocode work (explained to someone familiar with C or Java)?
The Short Story
A famous computer scientist, Tarjan, wrote a book years ago. It contains absolutely bizarre pseudocode. Would someone please explain it?
The Long Story
Tarjan is known for many ...
5
votes
1answer
553 views
Where are C++ templates inside of the lambda cube?
C++ templates have type variables and can express lambdas, so they must have System F embedded. But is that exactly where they are located in the lambda cube? Can C++ templates produce new types or ...
3
votes
0answers
35 views
Computability of Kolmogorov complexity in total languages
It is well known that the Kolmogorov complexity is uncomputable in Turing-complete programming languages. However, what about total programming languages?
For example, is the Kolmogorov complexity of ...
1
vote
1answer
60 views
Reason programming language B was named “B”?
I’ve searched around for this already but ironically the results have been overshadowed by “Why C was named C” instead.
If C was named “C” because it came after B, why was B named "B", since the only ...
-1
votes
2answers
52 views
Are managed computer programming languages eco-friendly?
Managed code needs to be be interpreted or JIT-ed at runtime.
At first glance it seems to me that in general it is more energy consuming to interpret/compile the program on every user's computer than ...
1
vote
0answers
30 views
How to create model for a powerful language whose programs are guaranteed to terminate?
I'm creating a powerful regular expression matching system that can be augmented by adding small microprograms to deterministic finite automaton (DFA) states. The microprogram solves the big bang ...
1
vote
2answers
100 views
Are the capabilities of programming languages the same?
Is the capability of every programming language the same since it is eventually translated into machine code. Python, Java etc. are all together instructions the CPU is going to process. So, you could ...
0
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0answers
41 views
Mathematical resource material accompanying TAPL
I'm currently reading Types and Programming Languages by Benjamin C. Pierce and just arrived at chapter 21 Metatheory of Recursive Types.
Prior to this chapter I found the book challenging but ...
2
votes
1answer
62 views
How do I count the exact number of executed commands for a MIPS program?
I want to know what the best way is to count the number of executed commands for a given MIPS program. Let's say we're given a simple for loop that counts from $0$ to $100$. For this I would write the ...
0
votes
2answers
71 views
Programming Language Hierarchy
I know that Assembly is the lowest level of the stack besides machine code, but are the languages above it all considered "high level languages" or is there a hierarchy amongst these languages. For ...
2
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3answers
80 views
Are there any programming languages which support user defined control structures?
For instance, the user would define a for each loop in their code as having a structure something like:
foreach([variable1] : [variable2]){
[statements]
}
(...
2
votes
1answer
42 views
How to make an unambigous grammar of a programming language
We know that the decision problem of whether an arbitrary context-free grammar is ambiguous is undecidable. My question is how are made the unambigous grammar of programming language? My guessing is ...
1
vote
0answers
39 views
Sequential valid programs to find novel outputs?
I have:
A programming language (P). Programs should take no input and produce a sequence of integers as output.
A way to enumerate all valid programs in this language (R) in a way that each program ...
0
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1answer
30 views
How to draw a parsing tree according to syntax diagram?
I would really appreciate if someone can explain the syntax diagram itself and can help to build the parsing tree.
0
votes
1answer
16 views
Examples of interesting semantics to study during a small project for a graduate Semantics course
I have been following the course Concrete Semantics with Isabelle/HOL. At some point we are given the task to verify a program/extend some semantic construction/prove some mathematical fact. I ...
3
votes
1answer
59 views
Is there a generally accepted name for creating types that select a subset of other types?
Tl;Dr;
Given:
type A = { int: foo, int: bar }
type B = select foo from A
What is the name of the typing relationship between A and B?
What is the name of the ...
1
vote
0answers
23 views
directed edges in an undirected graph [duplicate]
Undirected graph is given which has M edges and N vertices we have to convert every edge from u−v to u→v or v→u such that the total outdegree of every vertex is even.
For example, consider a graph ...
2
votes
0answers
23 views
What are the pros and cons of context-oriented programming (COP)?
I have started reading about COP, but can't really get a grip of it. What I understand is that you use layers to let the software dynmically adapt depending on the context, and this would result in ...
3
votes
0answers
28 views
How do you resolve this paradox with the invariance theorem?
The invariance theorem of kolmogorov complexity states that for two different languages with complexity functions $K_1$ and $K_2$, we have
$$\exists c.\forall s. K_1(s) \le K_2(s) + c$$
Here is an ...
1
vote
0answers
16 views
What are $(S,\Sigma)$-CCCs?
I was reading this and I was trying to understand the definition of $(S,\Sigma)$-CCC. The first requirement says:
a mapping [[_]] : S → |C|, associating some object [[s]] ∈ |C| to
any s ∈ S;
...
5
votes
2answers
114 views
LET REC recursive expression static typing rule
I'm taking a programming languages course and had a question regarding the typing rules for a recursive let rec expression in a static typing system.
To be more ...
1
vote
3answers
111 views
Soundness and completeness w.r.t. programming languages
I'm studying programming languages (more specifically type systems) and came across a concept I couldn't quite wrap my head around: soundness and completeness.
I'm taking a class, and according to my ...
0
votes
0answers
24 views
Composition of compostion as a functor
"Composition of Composition" (i.e., (.) . (.)) in Haskell), has type ...
1
vote
1answer
38 views
PL: What solves the type isomorphism $X \cong (X \rightarrow \mathbf{2})$?
In Practical Foundations for Programming
Languages, on page 138 (page 156 of the pdf), it says:
Requiring solutions to all type equations may seem suspicious, because
we know by Cantor’s Theorem ...
0
votes
0answers
26 views
What are the guiding design principles for designing programming languages that allow Sketching?
I wanted to implement and design my own programming language that allowed sketching, like Combinatorial Sketching for finite programs. I was reading through the paper but it was unclear to me if there ...
0
votes
0answers
40 views
Why is Combinatorial Sketching for Finite programs possible?
I was reading Combinatorial Sketching for Finite Programs and wanted to understand why synthesis of the sketching language was possible/feasible.
As far as I understand a partial program is ...
0
votes
1answer
76 views
First-order vs Higher-order Programs
Can someone explain the difference between first-order programs and higher-order programs in the context of programming languages?
My understanding so far is that Functional Languages (most) use ...
0
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1answer
163 views
What is the difference between “algorithm,” “process” and “program”?
I am currently studying algorithms and algorithmic design, and I am confused those terms. What is the difference between them?
Thank you.
0
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0answers
22 views
What is an intuitive way to understand the definition of Curry and Uncurry in Categorical Language?
I was studying the definition of currying and uncurrying using Category Theory from these slides. The answer and the proof on slide 19 makes 100% sense to me however, the definitions seem to come out ...
0
votes
1answer
34 views
Would hypercomputation machines be capable of simulating/computing/programming everything?
If uncomputable numbers existed, could this hypercomputation machines compute them? Could hypercomputation compute all types of uncomputable things? Even truly inconsistent things? Even things that ...
4
votes
0answers
51 views
What is the difference between A-normalization and K-normalization in compilers?
Administrative normal form is a program intermediate representation in which each immediate instruction has a name. It is used in GHC and OCaml.
K-normalized form is an intermediate representation in ...
1
vote
1answer
48 views
Meta Programming Operators
I have a basic understanding how operators work (bitwise, logical, unary, ternary, etc.), but I am confused how you define what the operator does so the machine knows how to treat the operator when ...
4
votes
1answer
91 views
What's the difference between environment and memory in terms of programming languages?
I've been reading up on programming languages to better my understanding with the textbook Essentials of Programming Languages (3e) - Friedman & Wand.
In a chapter regarding the states of ...
1
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0answers
46 views
Is there a distinction between pointers and references? [closed]
If so, what are the similarities and differences between the two? I’ve only worked with properties while programming.
1
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0answers
33 views
Why the name static and dynamic in static and dynamic scoping
I am wondering, from where static and dynamic scoping got their names.
After understanding the concept of static and dynamic scoping in C, what I assume is that whenever we failed to find out the ...
0
votes
1answer
16 views
CLRS pseudocode involving both subscripting and property access of a data structure
In Introduction to Algorithms, the stack data structure's enqueue operation has the following pseudocode
...
3
votes
0answers
41 views
An instance when you can eliminate propositional double negation in coq
Suppose st: string -> nat and X stands for the string 'X'.
Given the hypothesis ...
2
votes
0answers
41 views
Why interaction net languages use interaction rules to represent their syntaxes?
What I have looked up into:
here, here and here
What I have learnt:
What is an interaction net, its deduction & interaction rules,
How deduction rules can be changed into interaction rules -- ...
0
votes
1answer
18 views
Is it possible to define a pairwise function that can either append to a tuple or make a tuple, potentially with nested tuples?
I lack the vocabulary to appropriately express the question succinctly, so I apologize if the title question is confusing.
Suppose you can define a binary infix operator that produces tuples, and you ...
2
votes
2answers
78 views
How does one show $(\lambda x . (\lambda y.x))yx \equiv_{\beta} y$ in lambda calculus?
I wanted to show:
$$ (\lambda x . (\lambda y.x))yx \equiv_{\beta} y $$
the definition of beta equivalence is on page 17 of these notes.
I did a few attempts but got different things like $x$. I ...
2
votes
1answer
46 views
How do we show $\lambda x . x (\lambda y .y) \equiv_{\alpha} \lambda y.y (\lambda x . x)$ in lambda calculus?
How do we show $$\lambda x . x (\lambda y .y) \equiv_{\alpha} \lambda y.y (\lambda x . x)$$?
I was going through the slides here and it asked to do the above but by page 16 of the slides we have not ...
1
vote
1answer
18 views
Showing that an equivalence relation on programs need not be a congruence
An optional exercise from Programming Language Foundations asks
Can you think of a relation on commands that is an equivalence but not
a congruence?
An equivalence here refers to an ordinary ...
0
votes
1answer
47 views
Bounded Quantification: Full F<: intuition
I'm currently looking into Chapter 26 of Types and Programming Languages and am a bit confused by the "intuition" for Full F<: (p. 395):
A type T = ∀X<:T1.T2 describes a collection of ...
3
votes
2answers
496 views
Do “compiler” and “assembler” correspond to frontend and backend phases of a compiler?
In Compilers: Principles, Techniques, and Tools (2nd Edition) 2nd Edition
by Alfred V. Aho (Author), Monica S. Lam (Author), Ravi Sethi (Author), Jeffrey D. Ullman (Author) , Figure 1.5 gives a ...
