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language FAQ entry on braces and semicolons

R=rsc, iant, gri
CC=golang-dev
https://golang.org/cl/196075
This commit is contained in:
Rob Pike 2010-02-01 20:45:29 +11:00
parent 68796b0270
commit cecd163625

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@ -175,6 +175,36 @@ with the STL, a library for a language whose name contains, ironically, a
postfix increment.
</p>
<h3 id="semicolons">
Why are there braces but no semicolons? And why can't I put the opening
brace on the next line?</h3>
<p>
Go uses brace brackets for statement grouping, a syntax familiar to
programmers who have worked with any language in the C family.
Semicolons, however, are for parsers, not for people, and we wanted to
eliminate them as much as possible. To achieve this goal, Go borrows
a trick from BCPL: the semicolons that separate statements are in the
formal grammar but are injected automatically, without lookahead, by
the lexer at the end of any line that could be the end of a statement.
This works very well in practice but has the effect that it forces a
brace style. For instance, the opening brace of a function cannot
appear on a line by itself.
</p>
<p>
Some have argued that the lexer should do lookahead to permit the
brace to live on the next line. We disagree. Since Go code is meant
to be formatted automatically by
<a href="http://golang.org/cmd/gofmt/"><code>gofmt</code></a>,
<i>some</i> style must be chosen. That style may differ from what
you've used in C or Java, but Go is a new language and
<code>gofmt</code>'s style is as good as any other. More
important&mdash;much more important&mdash;the advantages of a single,
programmatically mandated format for all Go programs greatly outweigh
any perceived disadvantages of the particular style.
Note too that Go's style means that an interactive implementation of
Go can use the standard syntax one line at a time without special rules.
</p>
<h3 id="garbage_collection">
Why do garbage collection? Won't it be too expensive?</h3>
<p>