mirror of
https://github.com/golang/go
synced 2024-11-22 03:34:40 -07:00
214 lines
5.9 KiB
HTML
214 lines
5.9 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
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"http://www.w3.org/TR/html4/transitional.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=utf-8">
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<title>The Go Programming Language Design FAQ</title>
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<link rel="stylesheet" type="text/css" href="style.css">
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<script type="text/javascript" src="godocs.js"></script>
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</head>
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<body>
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<div id="topnav">
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<table summary=""><tr>
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<td id="headerImage">
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<a href="./"><img src="./logo_blue.png" height="44" width="120" alt="Go Home Page" style="border:0" /></a>
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</td>
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<td id="headerDocSetTitle">The Go Programming Language</td>
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</tr>
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</table>
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</div>
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<div id="linkList">
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<ul>
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<li class="navhead">Related Guides</li>
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<li><a href="go_tutorial.html">Tutorial</a></li>
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<li><a href="go_spec.html">Language Specification</a></li>
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<li><a href="go_lang_faq.html">FAQ</a></li>
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<li class="blank"> </li>
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<li class="navhead">Other Resources</li>
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<li><a href="./">Go Docs</a></li>
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<li><a href="/pkg">Library documentation</a></li>
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</ul>
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</div>
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<div id="content">
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<h1 id="The_Go_Programming_Language_Design_FAQ">The Go Programming Language Design FAQ</h1>
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<!-- The Table of Contents is automatically inserted in this <div>.
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Do not delete this <div>. -->
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<div id="nav"></div>
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<h2 id="creating_a_new_language">
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Why are you creating a new language?</h2>
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<p>
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TODO
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</p>
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<h2 id="history">
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What is the history of the project?</h2>
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<p>
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TODO
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</p>
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<h2 id="ancestors">
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What are Go's ancestors?</h2>
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<p>
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Go is in the C family, but also borrows some ideas from CSP-inspired
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languages such as Newsqueak and Limbo. The interface idea may be
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related to other languages but was designed in isolation; ditto
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packages. In every respect the language was designed by thinking
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about what programmers do and how to make programming, at least the
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kind of programming we do, more effective, which means more fun.
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</p>
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<h2 id="protagonists">
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Who are the protagonists?</h2>
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<p>
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Robert Griesemer, Rob Pike and Ken Thompson laid out the goals and
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original specification of the language. Ian Taylor read the draft
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specification and decided to write <code>gccgo</code>. Russ
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Cox joined later and helped move the language and libraries from
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prototype to reality.
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</p>
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<h2 id="different_syntax">
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Why is the syntax so different from C?</h2>
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<p>
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Other than declaration syntax, the differences are not major and stem
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from two desires. First, the syntax should feel light, without too
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many mandatory keywords, repetition, or arcana. Second, the language
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has been designed to be easy to parse. The grammar is conflict-free
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and can be parsed without a symbol table. This makes it much easier
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to build tools such as debuggers, dependency analyzers, automated
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documentation extractors, IDE plug-ins, and so on. C and its
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descendants are notoriously difficult in this regard but it's not hard
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to fix things up.
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</p>
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<h2 id="declarations_backwards">
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Why are declarations backwards?</h2>
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<p>
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They're only backwards if you're used to C. In C, the notion is that a
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variable is declared like an expression denoting its type, which is a
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nice idea, but the type and expression grammars don't mix very well and
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the results can be confusing; consider function pointers. Go mostly
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separates expression and type syntax and that simplifies things (using
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prefix <code>*</code> for pointers is an exception that proves the rule). In C,
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the declaration
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</p>
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<pre>
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int* a, b;
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</pre>
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<p>
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declares a to be a pointer but not b; in Go
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</p>
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<pre>
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var a, b *int;
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</pre>
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<p>
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declares both to be pointers. This is clearer and more regular.
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Also, the <code>:=</code> short declaration form argues that a full variable
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declaration should present the same order as <code>:=</code> so
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</p>
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<pre>
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var a uint64 = 1;
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</pre>
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has the same effect as
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<pre>
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a := uint64(1);
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</pre>
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<p>
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Parsing is also simplified by having a distinct grammar for types that
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is not just the expression grammar; keywords such as <code>func</code>
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and <code>chan</code> keep things clear.
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</p>
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<h2 id="no_pointer_arithmetic">
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Why is there no pointer arithmetic?</h2>
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<p>
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Safety. Without pointer arithmetic it's possible to create a
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language that can never derive an illegal address that succeeds
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incorrectly. Compiler and hardware technology has advanced to the
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point where a loop using array indices can be as efficient as a loop
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using pointer arithmetic. Also, the lack of pointer arithmetic can
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simplify the implementation of the garbage collector.
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</p>
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<h2 id="inc_dec">
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Why are <code>++</code> and <code>--</code> statements and not expressions? And why postfix, not prefix?</h2>
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<p>
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Without pointer arithmetic, the convenience value of pre- and postfix
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increment operators drops. By removing them from the expression
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hierarchy altogether, expression syntax is simplified and the messy
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issues around order of evaluation of <code>++</code> and <code>--</code>
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(consider <code>f(i++)</code> and <code>p[i] = q[i++]</code>)
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are eliminated as well. The simplification is
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significant. As for postfix vs. prefix, either would work fine but
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the postfix version is more traditional; insistence on prefix arose
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with the STL, part of a language whose name contains, ironically, a
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postfix increment.
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</p>
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<h2 id="TODO">
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TODO</h2>
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<p>TODO:</p>
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<pre>
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Why does Go not have:
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- assertions
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- exceptions
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- generic types
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What do you have planned?
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- variant types?
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explain:
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package designa
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slices
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oo separate from storage (abstraction vs. implementation)
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goroutines
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why garbage collection?
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no data in interfaces
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concurrency questions:
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why aren't maps atomic
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why csp
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inheritance?
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embedding?
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dependency declarations in the language
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oo questions
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dynamic dispatch
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clean separation of interface and implementation
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why no automatic numeric conversions?
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make vs new
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</pre>
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</div>
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<div id="footer">
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<p>Except as noted, this content is
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licensed under <a href="http://creativecommons.org/licenses/by/3.0/">
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Creative Commons Attribution 3.0</a>.
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</div>
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</body>
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</html>
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