An EDN (Extensible Data Notation) Objective C I/O library for MacOS and iOS.
The library includes:
-
MPEdnParser
, a parser for reading EDN and generating equivalent Cocoa data structures. -
MPEdnWriter
, which writes Cocoa data structures as EDN.
For most uses, parsing EDN is as simple as:
[@"{:a 1}" ednStringToObject];
Which returns the parsed object or nil on error.
And to generate EDN from a Cocoa object:
[myObject objectToEdnString];
See the headers for API docs.
To use the library, use one of (in decreasing order of ease-of-use):
-
Install via CocoaPods: add
pod 'MPEDN', '~> 1.0.0'
to your Podfile. -
Use a workspace containing your project and MPEdn as described here. You may also need to add the
-all_load
flag to the "Other Linker Flags" section of your project if theednStringToObject
andobjectToEdnString
category methods do not get linked in. -
Generate
libMPEdn.a
using the supplied Xcode project and copy that and the.h
files to your project.
-
EDN map <->
NSDictionary
(but see[MPEdnParser newDictionary]
to override). -
EDN list or vector <->
NSArray
(but see[MPEdnParser newArray]
to override). -
EDN set <->
NSSet
(but see[MPEdnParser newSet]
to override). -
EDN string <->
NSString
. -
EDN float <->
NSNumber
(numberWithDouble
). -
EDN int <->
NSNumber
(numberWithLong
). TheN
(bigint) suffix is not supported. -
EDN decimal ('M' suffix,
BigDecimal
in Clojure) <->NSDecimalNumber
. -
EDN boolean <->
NSNumber
(numberWithBool
). -
EDN character <->
MPEdnCharacter
. Objective-C does not have a separate character type comparable to EDN's: ObjC code tends to either use single-character strings or C-style unsigned bytes (which cannot be distinguished reflectively from any other NSNumber-based types). -
EDN keyword <->
MPEdnKeyword
. If theMPEdnWriter.useKeywordsInMaps
property is true (the default is false as of 0.2), strings used as keys inNSDictionary
will be output as keywords if possible. Note that strings and keywords never compare as equal, so this could get confusing when reading a dictionary from an external service that uses keywords: in general, prefer explicit use of keywords where possible. -
EDN symbol <->
MPEdnSymbol
. -
EDN tagged values can be translated by tag reader/writer classes implementing
MPEdnTaggedValueWriter
and/orMPEdnTaggedValueReader
(seeMPEdnBase64Codec
for an example). You can accept any tag regardless of whether there is a reader for it or not by setting theallowUnknownTags
property onMPEdnParser
, which will represent unknown tagged values withMPEdnTaggedValue
instances.MPEdnWriter
knows how to outputMPEdnTaggedValue
's which enables round-tripping of EDN with unknown tags.
-
Floats are output in full to avoid loss of precision.
-
Newlines in strings are output in their escaped form (
\n
rather than a raw0x0a
) even though the raw form is legal in order to make it straightforward to use generated EDN strings in line-oriented protocols. -
The parser and writer fully support all Unicode code points in string values (i.e. both 'normal' characters and UTF-16 surrogate pairs), but not elsewhere. Adding general support would be straightforward, at the cost of some speed, but since EDN syntax is defined in terms of ASCII character classes it's not clear that using anything but ASCII outside of strings would be valid EDN in any case.
MPEdn is developed by Matthew Phillips ([email protected]). It is licensed under the same open source license as Clojure, the Eclipse Public License v1.0 .