Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Parsing with Blocks
Search
Chris Eidhof | @chriseidhof
May 08, 2014
Technology
2
230
Parsing with Blocks
CocoaHeads Hamburg
Chris Eidhof | @chriseidhof
May 08, 2014
Tweet
Share
More Decks by Chris Eidhof | @chriseidhof
See All by Chris Eidhof | @chriseidhof
Dutch FP Day 2015
chriseidhof
2
380
Tiny Networking in Swift
chriseidhof
2
19k
Functional Swift - Brooklyn
chriseidhof
3
1.2k
Functional Swift - SF
chriseidhof
6
26k
Functional Swift
chriseidhof
6
1.3k
Functional Swift
chriseidhof
1
140
Functional Programming in Swift
chriseidhof
40
19k
Lighter View Controllers
chriseidhof
4
190
Practical Concurrent Programming
chriseidhof
4
270
Other Decks in Technology
See All in Technology
データ戦略部門 紹介資料
sansan33
PRO
1
3.1k
会社員しながら本を書いてきた知見の共有
sat
PRO
3
690
GigaViewerにおけるMackerel APM導入の裏側
7474
0
460
技術書典18結果報告
mutsumix
2
180
エンジニアが組織に馴染むために勉強会を主催してチームの壁を越える
ohmori_yusuke
2
120
GitHub Coding Agent 概要
kkamegawa
1
1.7k
Introduction to Sansan for Engineers / エンジニア向け会社紹介
sansan33
PRO
5
38k
OSMnx Galleryの紹介
mopinfish
0
150
S3 Tables を図解でやさしくおさらい~基本から QuickSight 連携まで/s3-tables-illustrated-basics-quicksight
emiki
2
340
kintone開発組織のDevOpsへの移り変わりと実践
ueokande
1
130
Digitization部 紹介資料
sansan33
PRO
1
3.8k
積み上げられた技術資産と向き合いながら、プロダクトの信頼性をどう守るか
plaidtech
PRO
0
940
Featured
See All Featured
How to Ace a Technical Interview
jacobian
276
23k
What's in a price? How to price your products and services
michaelherold
245
12k
YesSQL, Process and Tooling at Scale
rocio
172
14k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
5.8k
Being A Developer After 40
akosma
91
590k
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
47
2.8k
Unsuck your backbone
ammeep
671
58k
Designing Experiences People Love
moore
142
24k
GitHub's CSS Performance
jonrohan
1031
460k
GraphQLとの向き合い方2022年版
quramy
46
14k
Transcript
Parsing with Blocks CocoaHeads Hamburg Chris Eidhof
Warning All of this is a bit crazy
Building languages is magical
stylesheet { multiplier = if(slide.onlyHeader, 2, 1), baseFontSize = 45
* multiplier, splitBaseFontSize = 25, backgroundColor = colorScheme.backgroundColor, bodyFont = { family = "Apercu", color = colorScheme.textColor, size = baseFontSize } }
DSLs → SQL → AutoLayout → NSPredicate → Regular Expressions
→ ActiveRecord
DSLs External vs. Internal
DSLs: External → SQL → CSS → NSPredicate format syntax
DSLs: Internal [view1 mas_makeConstraints:^(MASConstraintMaker *make) { make.top.equalTo(superview.mas_top).with.offset(padding.top); make.left.equalTo(superview.mas_left).with.offset(padding.left); make.bottom.equalTo(superview.mas_bottom).with.offset(-padding.bottom); make.right.equalTo(superview.mas_right).with.offset(-padding.right);
}] Source: Masonry
V:[topField]-10-[bottomField] [flexibleButton(>=70,<=100)] |-[find]-[findNext]-[findField(>=20)]-|
None
Building an external DSL
None
Parsing 1. String → Stream of tokens 2. Stream of
tokens → Syntax Tree 3. Interpret Syntax Tree
Existing approaches → Hand-rolled parsers → Parser generators → ParseKit
/ CoreParse
An alternative approach → Based on functional programming → Backtracking
→ Immutable objects
The language
1 + 2 * 3 Expr ← Sum Sum ←
Product '+' Product Product ← Atom '*' Atom Atom ← Number
1 + 2 * 3 Expr ← Sum Sum ←
Product '+' Product | Product Product ← Atom '*' Atom | Atom Atom ← Number
(1 + 2) * 3
(1 + 2) * 3 Expr ← Sum Sum ←
Product '+' Product | Product Product ← Atom '*' Atom | Atom Atom ← Number | '(' Expr ')'
Block Syntax returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...}; Source: http://goshdarnblocksyntax.com
Live Coding
A stylesheet language
stylesheet { multiplier = if(slide.onlyHeader, 2, 1), baseFontSize = 45
* multiplier, splitBaseFontSize = 25, backgroundColor = colorScheme.backgroundColor, bodyFont = { family = "Apercu", color = colorScheme.textColor, size = baseFontSize } }
Rule stylesheet = ^(State *p) { __block NSArray *functions =
nil; return p.identifier().token(@"{"). manySepBy(method, comma).bind(to(functions)). token(@"}").yield(^id { return [[StylesheetObject alloc] initWithFunctions:functions]; }); };
Rule method = ^(State * p) { __block NSString* name
= nil; __block id body= nil; __block NSArray *parameters = nil; return p.identifier().bind(to(name)). optional(parameterList).bind(to(parameters)). token(@"="). rule(self.expression).bind(to(body)). yield(^id { return [[StylesheetFunction alloc] initWithName:name body:body parameters:parameters]; }); };
Rule mulExpression = infix(@"*", infix(@"/", functionCallExpression)); Rule addExpression = infix(@"+",
infix(@"-", mulExpression));
API
typedef State *(^Rule)(State *p);
@interface State : NSObject @property (nonatomic, strong) id result; @property
(nonatomic) BOOL failed; @property (nonatomic) NSString *errorMessage; @property (nonatomic) State *(^token)(NSString *); @property (nonatomic) State *(^identifier)(); @property (nonatomic) State *(^yield)(id (^)()); @property (nonatomic) State *(^bind)(void(^)(id result)); @property (nonatomic) State *(^oneOf)(NSArray *); @property (nonatomic) State *(^optional)(Rule); @property (nonatomic) State *(^eof)(); @property (nonatomic) State *(^rule)(Rule); @end
State Internals @interface State () @property (nonatomic) NSArray *tokens; @property
(nonatomic) NSUInteger tokenIndex; @end
self.token = ^(NSString* token) { if (self.failed) return self; NSString*
peek = self.peek; if ([token isEqual:peek]) { return [self next:peek]; } else { NSString* msg = [NSString stringWithFormat:@"Expected '%@', saw '%@'", token, peek]; return [self fail:msg]; } };
- (State *)next:(id)result { if (self.failed) return self; State *next
= [self copy]; next.failed = NO; next.result = result; next.tokenIndex++; return next; }
We created two DSLs → One for parsing (embedded) →
One external https://github.com/chriseidhof/parsingwithblocks
Thanks → @chriseidhof → http://www.objc.io → http://www.uikonf.com → http://www.decksetapp.com