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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.

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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 ...
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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
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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
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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
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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-...
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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
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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
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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
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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
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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 ...
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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 ...
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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.
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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
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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 ...
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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 ...
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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
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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 ...
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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; ...
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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 ...
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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 ...
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0answers
24 views

Composition of compostion as a functor

"Composition of Composition" (i.e., (.) . (.)) in Haskell), has type ...
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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 ...
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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 ...
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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
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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.
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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 ...
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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
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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 ...
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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
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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 ...
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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.
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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 ...
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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
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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
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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
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...