How to read code

A lightning talk in the office

Transcript

1. How to read code
   Shimpei Makimoto!
   2014-09-24
   

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2. Shimpei Makimoto!
   Software Engineer
   photo by r7kamura
   @makimoto @makimoto
   

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3. Today's talk
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5. άϦονɾΞʔτΛ८ͬͯަΘ͞ΕΔٞ࿦ͷதʹ͸ɼάϦον͕ΘΕΘΕʹ༩͑Δ৺৅ͦ͜ຊ࣭ͩͱ͢Δཱ৔͕͋Γ·͢ɽͦͷཱ৔
   ʹཱͭਓʑ͸ਅͷάϦον͸࠶ݱͰ͖ͳ͍ͱݴ͍ɼͦΕΒ͸ҰॠͰফ͑ڈΔͱݴ͍·͢ɽ࠶ݱͰ͖ͳ͍ͱओு͢ΔҎ্ɼ൴Β͸άϦο
   νɾΞʔτΛάϦονൈ͖Ͱߏ੒͠ͳͯ͘͸ͳΒͳ͍Ͱ͠ΐ͏ɽҰํͰɼϐΫηϧΛዞҙతʹฒͼସ͑ͨΓมܗͤͨ͞Γͨ͠ਤ૾Λ
   ΋ͬͯάϦονɾΞʔτͱ͢Δཱ৔͕͋Γ·͢ɽͦͷཱ৔͔ΒݟΔͱɼάϦονɾΞʔτͱ͸άϦονͷࢹ֮ޮՌΛϞνʔϑͱͨ͠
   ਓ޻తͳΞʔτ࡞඼ͱ͍͏͜ͱʹͳΓ·͢ɽ
   !
   ͜ͷɼ৺৅ͱͯ͠ͷάϦονͱϞνʔϑͱͯ͠ͷάϦον͸ɼάϦονͱ͍͏ݱ৅Λத৺ʹɼೋۃ΁ဃ཭͠ͳ͕ΒɼάϦονɾΞʔ
   τΛݻఆ͠͸͡Ί͍ͯ·͢ɽ͓ͦΒ͘কདྷతʹ͸ɼલऀͷओு͸άϦον࿦΍ඒֶͷจ຺΁ྲྀΕͯΏ͘Ͱ͠ΐ͏ɽޙऀ͸ΑΓҰൠత
   ͳҙຯͰάϦονɾΞʔτͷ໊Λ֫ಘͯ͠Ώ͘ʹҧ͍͋Γ·ͤΜɽάϦονɾϛϡʔδοΫͷઌྫʹؑΈͯ΋ɼͦΕ͸ࣗ͘͝વͳ੒
   Γߦ͖ͩͱࢥΘΕ·͢ɽ
   VDOW
   
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6. Step 0: Read the spec
   (roughly)
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7. Step 1: Find files
   

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8. Step 2: Understand data
   structure (1)
   http://golang.org/src/pkg/image/png/reader.go
   

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9. Step 2: Understand data
   structure (2)
   http://golang.org/src/pkg/image/png/reader.go
   http://golang.org/pkg/image/
   

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10. Step 3: Specify important
    public methods
    http://golang.org/src/pkg/image/png/reader.go
    http://golang.org/pkg/image/png/
    

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11. Step 4: Reading
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16. func (d *decoder) decode()
    (image.Image, error)
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    DGDGF
    

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17. wrap up
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