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*To*: <srfi-48@xxxxxxxxxxxxxxxxx>*Subject*: Re: Format strings are wrong*From*: Paul Schlie <schlie@xxxxxxxxxxx>*Date*: Fri, 26 Dec 2003 19:35:41 +0100*Delivered-to*: srfi-48@xxxxxxxxxxxxxxxxx*Old-date*: Thu, 25 Dec 2003 15:36:42 -0500*User-agent*: Microsoft-Entourage/10.1.4.030702.0

Gentlemen, with all due respect, and understanding that the following thoughts may be best expressed in an alternative SRFI; but Upon reviewing the discussion archive, I feel compelled to voice support of Marc's opinions; as I don't believe C'ish embedded numerical format string hacks actually materially help porting code, or are particularly favored by folks who are familiar with C; but actually reduce the potential simplicity and efficiency of mixed text/numerical string formatting which the language could and arguably should otherwise encourage. Possibly something along the lines of simply adopting the notion that: (str-fmt ....) [or (string ...) be extended] to accept mixed string, symbol, character and numerical arguments, and produces a string resulting from the concatenation of its argument's string equivalences, by simply converting its arguments into strings if they're not already strings, using (number->string ...) or (symbol->string ...) etc. (define how-many 3) (define of-what 'apple) (str-fmt "I ate " 1/2 " of an " of-what ".") -> "I ate 1/2 of an apple." (str-fmt "I have " how-many " " of-what (if (not (= how-many 1)) "s") ".") -> "I have 3 apples." etc.. Which is likely sufficient for many things and fairly simple and intuitive. When more numerical format control is desired, it would seem most straight forward to simply define a more explicit generic (num->str ....) format function, which could support parameters such as how to treat signs, digit separation, field justification, leading/trailing zeros, significant digits, etc. Possibly: (num-fmt num-value '(['+|'p] ['s|'z] ['c N] ['m M] ['r R] ['e E])) [+|p] specifies sign formatting: + : signed values: +1 0 -1 p : paren'ed negatives: 1 0 (1) : default signed neg: 1 0 -1 [s|z] : leading/trailing fill s : space leading/trailing fill _1012 12.0__ (_ = space) z : zero leading/trailing fill 01012 12.000 : default none specified (reals always have at least one digit leading and trailing the decimal point) [c N] : N digit comma separator from radix point: 12,423,233.032,343, : default none specified [m M] specifies integer/mantissa digits of significance: m 0 : default representation significance, left justified, no fill m M : uses M max digits of significant right justified, no fill [r R] specified the integer/mantissa radix r 0: defaults to decimal r R: specifies maximum radix digit value (radix - 1) (where exponent values print showing xRADIX^decimal-exponent i.e. 1.23x10^+32, or 1.0110x2^32, etc) [e E] specifies minimum number of decimal exponent digits which are sign-prefixed etc.... Or something like that so that when more sophisticated numerical formatting is required, one could define pre-cooked format definition and use it: (define my-fmt (list '+ 'z 'c 3 'm 6 'r 10 'e 2)) (define my-num 1/4) (str-fmt "unformated: " my-num ", formatted: " (num-fmt my-num my-fmt)) -> "unformatted: 1/4, formatted: +0.25000x10^+00" Or something like that, thanks for your time and consideration. -paul-

**Follow-Ups**:**Re: Format strings are wrong***From:*Alex Shinn

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