I would like to give Sage some groundset and have it generate all possible matroids on that groundset. This is possible in e.g. Macaulay2; does any analogous method exist for Sage's matroids package?
Related
For a program i have to reformat a dot file in Haskell to adjust the layout of its tree/content. I decided to use https://hackage.haskell.org/package/graphviz-2999.20.1.0/docs/Data-GraphViz.html , but i cant find simple tutorials and the documentation confuses me, namely:
1 . It contains a function: dotToGraph, which reads: "A pseudo-inverse to graphToDot; "pseudo" in the sense that the original node and edge labels aren't able to be reconstructed."
I do need to retain the names of the nodes and edges, which i suppose are the labels mentioned here? but it seems weird that it cannot do this. It also does not take in a file name or string for the dot text, so i assume this is the wrong function.
2 . There also seems to be a parseDot function/class that comes with the package, but i cant find clear documentation for its use. (see: https://hackage.haskell.org/package/graphviz-2999.20.1.0/docs/Data-GraphViz-Parsing.html#t:ParseDot)
Can you recommend me a simple overview/summary/online example for doing this? Should i be using a different function? I have only recently started using Haskell, so the package documentation is sometimes difficult to decipher for me.
It would help a great deal, thanks!
Is it possible to get a list of all the arguments a constructor takes?
With the names and types of the parameters?
I want to automatically check the values of a JSON are good to use for building their equivalent as a class instance.
Preferably without macros... I have build a few, but I still find them quiet confusing.
Must work with neko and JS, if that maters.
Thanks.
I think you want to look at Runtime Type Information (rtti)
From the Haxe Manual: The Haxe compiler generates runtime type information (RTTI) for classes that are annotated or extend classes that are annotated with the #:rtti metadata. This information is stored as a XML string in a static field __rtti and can be processed through haxe.rtti.XmlParser. The resulting structure is described in RTTI structure.
Alternative; If you want to go with macros, this might be a good start
http://code.haxe.org/category/macros/add-parameters-as-fields.html
I would like to be able to provide to my Haskell app and config file written in Haskell. The reason why is because I would like the user to be able to provide a few custom functions.
Is it possible to load a haskell file at runtime, even though it might depend on some type provided by the app itself.
At the moment, I have a super main function, and I build a new executable per config file. The file basically, declares some hooks and call super main with them. The problem with that is, at the moment I have to define a new target for each config in my cabal file (I use a sandbox, and I don't want to have to install any library part of my package). I thought using runghc instead but I do I make it works with the sandbox ? I've seen there is a 'plugin' package on hackage but it does't seem to be up to date. What is the common way to deal with this type of problem ?
dyre looks like it fits the bill.
I'd like to generate XML picklers for an XSD file. It seems like a useful tool that might already exist. Does it?
HaXml does have a tool for generating Haskell data types from DTDs and a tool for generating Haskell data types from XSDs: http://hackage.haskell.org/package/HaXml
The executables are named XsdToHaskell and DtdToHaskell.
If you're on Windows and you have PATH modified by Haskell Platform, you'll need to call it like this: xsdtohaskell < path_to.xsd > path_to.hs
The generated files are a decent starting point.
I'm trying to write a program that will check the file type of a certain file and I found a haskell library that should do the trick.
The problem arises when I try to use it. I have no idea what I have to do, which function to call etc. The library is full of cryptic commands with no examples, no tutorial or a homepage.
Please help.
There is the package's documentation that contains short descriptions of the important functions (which are not that many). For additional information about what the underlying C library does (and therefore also the Haskell library), have a look at libmagic's man page.
The basic usage should look similar to this (untested):
import Magic.Init
import Magic.Operations
main =
do magic <- magicOpen []
loadDefaultMagic magic
magicFile magic "/my/file" >>= print