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author | Oscar Campbell <oscar@campbell.nu> | 2015-06-14 18:36:35 +0200 |
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committer | Oscar Campbell <oscar@campbell.nu> | 2015-06-14 18:36:35 +0200 |
commit | ed73a90bd3192f4994cc467f71900b62e39b0ec0 (patch) | |
tree | 3c6e189b7760c4755f7bb6beea6b931bc37c189a /doc | |
parent | 2782cddb56b2f3b56893915bc227839dc3d246c0 (diff) | |
download | Nim-ed73a90bd3192f4994cc467f71900b62e39b0ec0.tar.gz |
Regarding num literals, mod paths, ident equality.
Diffstat (limited to 'doc')
-rw-r--r-- | doc/manual/lexing.txt | 27 | ||||
-rw-r--r-- | doc/manual/modules.txt | 8 |
2 files changed, 26 insertions, 9 deletions
diff --git a/doc/manual/lexing.txt b/doc/manual/lexing.txt index fab6da416..9419f8453 100644 --- a/doc/manual/lexing.txt +++ b/doc/manual/lexing.txt @@ -101,25 +101,28 @@ Two identifiers are considered equal if the following algorithm returns true: .. code-block:: nim proc sameIdentifier(a, b: string): bool = - a[0] == b[0] and a.replace("_", "").toLower == b.replace("_", "").toLower + a[0] == b[0] and + a.replace(re"_|–", "").toLower == b.replace(re"_|–", "").toLower That means only the first letters are compared in a case sensitive manner. Other -letters are compared case insensitively and underscores are ignored. +letters are compared case insensitively and underscores and en-dash (Unicode +point U+2013) are ignored. -This rather strange way to do identifier comparisons is called +This rather unorthodox way to do identifier comparisons is called `partial case insensitivity`:idx: and has some advantages over the conventional case sensitivity: It allows programmers to mostly use their own preferred -spelling style and libraries written by different programmers cannot use -incompatible conventions. A Nim-aware editor or IDE can show the identifiers as -preferred. Another advantage is that it frees the programmer from remembering +spelling style, be it humpStyle, snake_style or dash–style and libraries written +by different programmers cannot use incompatible conventions. +A Nim-aware editor or IDE can show the identifiers as preferred. +Another advantage is that it frees the programmer from remembering the exact spelling of an identifier. The exception with respect to the first letter allows common code like ``var foo: Foo`` to be parsed unambiguously. -Historically, Nim was a `style-insensitive`:idx: language. This means that it -was not case-sensitive and underscores were ignored and there was no distinction -between ``foo`` and ``Foo``. +Historically, Nim was a fully `style-insensitive`:idx: language. This meant that +it was not case-sensitive and underscores were ignored and there was no even a +distinction between ``foo`` and ``Foo``. String literals @@ -345,6 +348,12 @@ notation: ``0B0_10001110100_0000101001000111101011101111111011000101001101001001'f64`` is approximately 1.72826e35 according to the IEEE floating point standard. +Literals are bounds checked so that they fit the datatype. Non base-10 +literals are used mainly for flags and bit pattern representations, therefore +bounds checking is done on bit width, not value range. If the literal fits in +the bit width of the datatype, it is accepted. +Hence: 0b10000000'u8 == 0x80'u8 == 128, but, 0b10000000'i8 == 0x80'i8 == -1 +instead of causing an overflow error. Operators --------- diff --git a/doc/manual/modules.txt b/doc/manual/modules.txt index fe3360773..813505769 100644 --- a/doc/manual/modules.txt +++ b/doc/manual/modules.txt @@ -146,6 +146,14 @@ modules don't need to import a module's dependencies: var x: MyObject echo($x) +Note on paths +----------- +In module related statements, if any part of the module name / +path begins with a number, you may have to quote it in double quotes. +In the following example, it would be seen as a literal number '3.0' of type +'float64' if not quoted, if uncertain - quote it: +.. code-block:: nim + import "gfx/3d/somemodule" Scope rules ----------- |