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
150
Functional Programming in Swift
chriseidhof
40
19k
Lighter View Controllers
chriseidhof
4
200
Practical Concurrent Programming
chriseidhof
4
280
Other Decks in Technology
See All in Technology
Azure AI Foundryでマルチエージェントワークフロー
seosoft
0
150
より良いプロダクトの開発を目指して - 情報を中心としたプロダクト開発 #phpcon #phpcon2025
bengo4com
1
390
【TiDB GAME DAY 2025】Shadowverse: Worlds Beyond にみる TiDB 活用術
cygames
0
890
rubygem開発で鍛える設計力
joker1007
1
130
Agentic Workflowという選択肢を考える
tkikuchi1002
1
390
AI技術トレンド勉強会 #1MCPの基礎と実務での応用
nisei_k
1
250
ひとり情シスなCTOがLLMと始めるオペレーション最適化 / CTO's LLM-Powered Ops
yamitzky
0
380
GeminiとNotebookLMによる金融実務の業務革新
abenben
0
150
AWS アーキテクチャ作図入門/aws-architecture-diagram-101
ma2shita
29
9.5k
Liquid Glass革新とSwiftUI/UIKit進化
fumiyasac0921
0
140
ユーザーのプロフィールデータを活用した推薦精度向上の取り組み
yudai00
0
490
Amazon S3標準/ S3 Tables/S3 Express One Zoneを使ったログ分析
shigeruoda
2
390
Featured
See All Featured
Design and Strategy: How to Deal with People Who Don’t "Get" Design
morganepeng
130
19k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
48
2.8k
The MySQL Ecosystem @ GitHub 2015
samlambert
251
13k
It's Worth the Effort
3n
184
28k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
5.8k
Into the Great Unknown - MozCon
thekraken
39
1.9k
Save Time (by Creating Custom Rails Generators)
garrettdimon
PRO
31
1.2k
Bash Introduction
62gerente
614
210k
Principles of Awesome APIs and How to Build Them.
keavy
126
17k
The Cult of Friendly URLs
andyhume
79
6.4k
Fantastic passwords and where to find them - at NoRuKo
philnash
51
3.3k
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