Questions tagged [design-patterns]

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6
votes
1answer
1k views

Is there a way of objectively measuring the efficiency or quality of software or code design?

I've been thinking about ways of measuring code, and, quite frankly, I can't think of truly objective, semi-universal ways of evaluating the quality or "strength" of code to say, "Yes, this is better ...
4
votes
2answers
243 views

What's the difference between declarative syntax and encapsulation?

I had been first introduced to the idea of declarative syntax when using Angular JS. From what I understand, the idea is that you say, "do this" instead of "in order to do this, do this, this and this"...
3
votes
3answers
586 views

Design patterns for simple text based scripting language?

In my current application I am trying to determine the best way to implement a simple scripting language. This language would allow a user to create a script that controls a machine with various ...
3
votes
2answers
44 views

Is there a formal term for functions that have static state across executions?

Two examples, one in PHP: function adder($i){ static $a = 0; $a += $i; return $a; } A similar effect can be achieved with closures in javascript: ...
1
vote
1answer
40 views

design cache system using queuing theory

If we have data from a random population, a 3d histogram of throughput and current cache size of DRAM (intersection of a IOPS & a cache size will have a count). How can one use queuing theory to ...
1
vote
1answer
116 views

What is the difference between a “meta model” and “design patterns”?

Where is the difference between a "meta model" and "design patterns"? If you take, for example, Fowlers "Identity Field" from his book "Patterns Of Enterprise Application Architecture": Why is this a ...
1
vote
0answers
38 views

Building an architecture without pointers, objects, memory allocation or first class functions [closed]

Many sources for good software architecture will use objects, pointers, memory allocation in their solutions. The PLC programming language 61131-3 Structured Text is really limited in this regard, ...
1
vote
1answer
2k views

Combine abstract factory with decorator pattern [closed]

I'm working on a simple project of software engineering that should combine two patterns. I choose Abstract Factory and Decorator patterns to modify (dynamically) objects created with the concrete ...
0
votes
1answer
30 views

How does this example violate Liskov substitution principle, which then causes violation of the open-closed principle?

From Agile Principles, Patterns, and Practices in C# by Robert Martin, Listing 10-1. A violation of LSP causing a violation of OCP ...
0
votes
1answer
44 views

State Machine and State transition Table - Explanation and Creation Of

How do I create a state transition table/array in actual code/pseudo-code? I haven't experienced the "ah-ha" moment yet with the state machine to coding (and I really want to). I've looked at several ...
0
votes
0answers
21 views

Is there an appropriate design pattern for this problem?

In terms of good OOP design, what is the best way to structure the code described below. The data I have a set of commands. Each command has an identifier, deadline, and a set of jobs to be done. Each ...
0
votes
0answers
21 views

Abstract syntax tree: expression->operation->lhs|rhs vs expression->lhs|operation|rhs - what should I take into account in decision?

I am trying to build class hierarchy for the abstract syntax tree of First Order Logic as specified in the grammar https://github.com/antlr/grammars-v4/blob/master/fol/fol.g4 (ANTLR parser generator). ...
0
votes
0answers
16 views

How do I erase the “shadow-world” antipattern?

In this antipattern, you have level-0 constructs of the language, which are then abstracted over by creating level-1 constructions, and these level-1 abstractions are abstracted over by creating level-...
0
votes
0answers
30 views

What are the pros and cons of these two coding patterns/structures? And do they have a formal term?

I have traditionally been doing things like this: function test() // A { if (/* conditions */) return true; else return false; } Of late, ...
0
votes
0answers
32 views

Finite state machine for a modified traffic controller

Consider a traffic light controller for an intersection of a main street and a smaller street. Both streets are one-way streets. The intersection has two traffic lights, one for each street. In normal ...