Questions tagged [design-patterns]
The design-patterns tag has no usage guidance.
18 questions
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How to Think About Physical Design of Libraries in C++ When Considering the Deliverable's API?
Since design ideas, and even the concept of Physical Design (exactly where you put your files), are such a broad topic, may I give a definite example and ask for feedback on the example?
Suppose you ...
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Reference request for book on design patterns with foreword by Christopher Alexander
I do recall having found a book on software design patterns with a foreword by Christopher Alexander. Now, as is well known Alexander is credited as the creator of the concept of design patterns and ...
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Clarification about a sentence from GoF Design Patterns book
I'm currently reading Design Patterns: Elements of Reusable Object-Oriented Software by GoF and having trouble understanding the following sentence (page 19, Section 1.6):
Composition requires ...
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Is there one (or a few) canonical/ specific use cases for "functions returning functions" (beyond "decorators")?
Is there one (or a few) canonical/ specific use cases for "functions returning functions" (beyond "decorators")?
What can you do with "functions returning functions" ...
- 165
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1
answer
45
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system architecture or software architecture
I was trying to get started with a small project but I quickly realized I had to do more research on the subject.
Suppose, when creating a site, in production, there's a certain structure how the ...
- 21
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When to dynamically compute data vs. when to use variables and update on demand?
Two scenarios:
Function is called and data is computed and returned.
Data is saved in variable, updated when required, data is retrieved from variable.
So I was wondering in what kind of scenarios ...
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Best way to code a shopping cart consisting of items with different properties
This is an interview question. Interviewer wanted a scalable solution
Goal is to find value of shopping cart. Cart could have 3 different types of items(Physical,Digital,URL).
Only Physical Items have ...
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36
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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, ...
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1
answer
163
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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
...
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78
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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 ...
- 111
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75
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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, ...
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129
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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 ...
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1
answer
219
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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 ...
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3
answers
939
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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 ...
- 343
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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 ...
- 604
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2
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53
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:
...
- 131
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338
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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"...
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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 ...
