implicit-context 0.0.1
What if I told you that you could could have implicit parameters in D?
To use this package, run the following command in your project's root directory:
Manual usage
Put the following dependency into your project's dependences section:
implicit-context
What's this?
implicit-context
is a DUB package implementing an implicit context system for D as a library.
A context is a table of named values, and each thread has a TLS stack of hierarchical contexts. It is similar to namespaces or environment variables, as the top-most name get the lookup.
It is a secondary stack for your program, to be used to pass "contextual" parameters like:
- Allocators,
- Loggers,
- and anything belonging to "context".
This system is inspired by Odin, Scala, and Jai, but without language support:
- It doesn't change the ABI, nor is there a hidden parameter in function calls.
- But you need to call
context.push()
andcontext.pop()
manually, the language will not manage that for you.
Features
- Set and get context variables.
- Namespaced look-up, with masking.
- Hash-based lookup with 64-bit bloom to save on string comparisons.
- Includes basic contextual APIs built upon
implicit-context
: - Allocator
- Logger
- User Pointer
- D subset:
-betterC
-compatible,@nogc
,nothrow
. You need TLS and a C runtime though.
Usage
Set a context variable
// Create or update myInt to value 8.
context.set!int("myInt", 8);
Variable names MUST be valid D identifiers, else it's a programming error.
// Crash. "045" is an invalid identifier.
context.set!int("045", 1);
Get a context variable
// Retrieve value of myInt. This value is thread-local.
int myInt = context.get!int("myInt");
When using context.get
, an unknown variable identifier is a programming error and would crash:
int myInt = context.get!int("__non_Existing__"); // Crash
Use context.query
for an optional variable:
int myInt;
bool found = context.query!int("myInt");
Note: wrong type size will crash. Type mismatch with right size will silently succeed, currently.
Push and pop context scopes
context.push
: Push context, begin a new one.context.pop
: Pop context, restore previous values.
context.set!int("var", 4);
context.push;
context.set!int("var", 5); // mask former context variable
context.pop;
assert(context.get!int("var") == 4);
Using the Context Allocator API
How to allocate and reallocate:
// Allocate 1024 bytes.
void* p = context.allocator.malloc(1024);
// Change the allocation size to 24 bytes.
context.allocator.realloc(p, 24);
// Free the allocation.
context.allocator.free(p);
- Registered by ponce
- 0.0.1 released a year ago
- p0nce/implicit-context
- BSL-1.0
- Dependencies:
- none
- Versions:
-
0.0.1 2023-Sep-28 ~master 2023-Oct-01 - Download Stats:
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- Score:
- 0.1
- Short URL:
- implicit-context.dub.pm