CodeMirror

 /* D demo code // copied from phobos/sd/metastrings.d */ // Written in the D programming language. /** Templates with which to do compile-time manipulation of strings. Macros: WIKI = Phobos/StdMetastrings Copyright: Copyright Digital Mars 2007

            - 2009. License:

            <a href="http://www.boost.org/LICENSE_1_0.txt">Boost License 1.0</a>. Authors: $(WEB digitalmars.com, Walter Bright), Don Clugston Source: $(PHOBOSSRC std/_metastrings.d) */ /* Copyright Digital Mars 2007 - 2009. Distributed under the Boost Software License, Version 1.0. (See accompanying

            file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) */ module std.metastrings; /** Formats constants into a string at compile time. Analogous to $(XREF string,format). Parameters: A = tuple of constants, which can be strings,

            characters, or integral values. Formats: * The formats supported are %s for strings, and %% * for the % character. Example: --- import std.metastrings; import std.stdio; void main() { string s = Format!("Arg %s = %s", "foo", 27); writefln(s);

            // "Arg foo = 27" } * --- */ template Format(A...) { static if (A.length == 0) enum Format = ""; else static if (is(typeof(A[0]) : const(char)[])) enum Format = FormatString!(A[0], A[1..$]); else enum Format = toStringNow!(A[0]) ~ Format!(A[1..$]);

            } template FormatString(const(char)[] F, A...) { static if (F.length == 0) enum FormatString = Format!(A); else static if (F.length == 1) enum FormatString = F[0] ~ Format!(A); else static if (F[0..2] == "%s") enum FormatString = toStringNow!(A[0])

            ~ FormatString!(F[2..$],A[1..$]); else static if (F[0..2] == "%%") enum FormatString = "%" ~ FormatString!(F[2..$],A); else { static assert(F[0] != '%', "unrecognized format %" ~ F[1]); enum FormatString = F[0] ~ FormatString!(F[1..$],A);

            } } unittest { auto s = Format!("hel%slo", "world", -138, 'c', true); assert(s == "helworldlo-138ctrue", "[" ~ s ~ "]"); } /** * Convert constant argument to a string. */ template toStringNow(ulong v) { static if (v

            < 10) enum toStringNow=""

            ~ cast(char)(v + '0'); else enum toStringNow=t oStringNow!(v / 10) ~ toStringNow!(v % 10); } unittest { static assert(toStringNow!(1uL << 62)=="4611686018427387904" ); } /// ditto template toStringNow(long v) { static if (v < 0) enum toStringNow="-"

            ~ toStringNow!(cast(ulong) -v); else enum toStringNow=t oStringNow!(cast(ulong) v); } unittest { static assert(toStringNow!(0x100000000)=="4294967296" ); static assert(toStringNow!(-138L)=="-138" ); } /// ditto template toStringNow(uint U)

            { enum toStringNow=t oStringNow!(cast(ulong)U); } /// ditto template toStringNow(int I) { enum toStringNow=t oStringNow!(cast(long)I); } /// ditto template toStringNow(bool B) { enum toStringNow=B ? "true" : "false"; } /// ditto template toStringNow(string

            S) { enum toStringNow=S ; } /// ditto template toStringNow(char C) { enum toStringNow="" ~ C; } /******** * Parse unsigned integer literal from the start of string s. * returns: * .value=t he integer literal as a string, * .rest=t he string

            following the integer literal * Otherwise: * .value=n ull, * .rest=s */ template parseUinteger(const(char)[] s) { static if (s.length==0 ) { enum value="" ; enum rest="" ; } else static if (s[0]>= '0' && s[0]

                <='9' ) { enum value=s [0] ~ parseUinteger!(s[1..$]).value; enum rest=p arseUinteger!(s[1..$]).rest; } else { enum value="" ; enum rest=s ; } } /******** Parse integer literal optionally preceded by $(D '-') from the start of

                string $(D s). Returns: .value=t he integer literal as a string, .rest=t he string following the integer literal Otherwise: .value=n ull, .rest=s */ template parseInteger(const(char)[] s) { static if (s.length==0 ) { enum value="" ; enum

                rest="" ; } else static if (s[0]>= '0' && s[0]

                    <='9' ) { enum value=s [0] ~ parseUinteger!(s[1..$]).value; enum rest=p arseUinteger!(s[1..$]).rest; } else static if (s.length>= 2 && s[0] == '-' && s[1] >= '0' && s[1]

                        <='9' ) { enum value=s [0..2] ~ parseUinteger!(s[2..$]).value; enum rest=p arseUinteger!(s[2..$]).rest; } else { enum value="" ; enum rest=s ; } } unittest { assert(parseUinteger!(

                        "1234abc").value=="1234" ); assert(parseUinteger!( "1234abc").rest=="abc" ); assert(parseInteger!( "-1234abc").value=="-1234" ); assert(parseInteger!( "-1234abc").rest=="abc" ); } /** Deprecated aliases held for backward compatibility.

                        */ deprecated alias toStringNow ToString; /// Ditto deprecated alias parseUinteger ParseUinteger; /// Ditto deprecated alias parseUinteger ParseInteger;