91d57e4e77
The original text only mentions the block statement and parentheses. But many other statements can use blocks, e.g. if, for, while.
57 lines
1.4 KiB
Markdown
57 lines
1.4 KiB
Markdown
---
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title: Blocks
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---
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# Blocks
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Blocks can be introduced in two different ways: by indenting statements or with `()`s.
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The first way ist to use indenting, e.g. using `if-elif-else`, `while`, `for` statements, or the `block` statement.
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``` nimrod
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if true:
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echo "Nimrod is great!"
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while false:
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echo "This line is never output!"
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block:
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echo "This line, on the other hand, is always output"
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```
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The `block` statement can also be labeled, making it useful for breaking out of loops and is useful for general scoping as well.
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``` nimrod
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block outer:
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for i in 0..2000:
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for j in 0..2000:
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if i+j == 3145:
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echo i, ", ", j
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break outer
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let b = 3
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block:
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let b = "3" # shadowing is probably a dumb idea
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```
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Parentheses can be used as an expression, but they do not provide end of statement inference, so it is necessary to place semicolons yourself. An interesting and unexpected side effect of this syntax is that Nim is suitable even for die-hard brace purists!
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While possible, it doesn't mean it's a good idea. Most Nim code does not use parentheses in that way, and it would not be seen as idiomatic.
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``` nimrod
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proc square(inSeq: seq[float]): seq[float] = (
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result = newSeq[float](len(inSeq));
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for i, v in inSeq: (
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result[i] = v*v;
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)
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)
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```
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<!-- XXX FIX
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square(( # A 1001 long sequence to be squared
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var result = newSeq[float]();
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for i in 0..1000:
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result.add(i);
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result
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))-->
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