---------- Forwarded message ---------- From: Alastair Leith <[email protected]> Date: 12 April 2010 01:06 Subject: Re: Javascript issue modifying a structure (again… :/) To: Christopher Wright <[email protected]>
Yes that helps heaps. Thanks cwright. I kind of twigged to the referencing thing a few weeks back but didn't really extrapolate the general rule (I was getting some strange results!) and still not 100% sure I have yet. So… Does the function you wrote also assign individual item references back to the original structure? If they are *values* and not *references* put into * newObj*, is that distinction because of the call to another function or just the iterating through at the lowest child level of the structure? If items had sub-items would I need to iterate though sub-items (in more function calls ? regressive function calls are out in JS aren't they?)? So many questions! I'm really grateful for your help already though, thanks again. Alastair I guess the downside of a loosely typed language like JS when your trying to teach yourself scripting (that's me btw ;) ) is that things can get a little slippery and not generate meaningful error mesages... On 12 April 2010 00:49, Christopher Wright <[email protected]> wrote: > If anybody could identify my misconception here I be very grateful: >> > > > You're assuming that you can modify inputs -- you can't. > > You're assuming that JS copies by value -- it doesn't (it copies by > reference). > > So, when you assign glyph to an input: glyph = glyphs[cursor]; glyph > is a reference to the input -- trying to modify that will fail. > > You need a copy function, as follows: > > function copy(obj) > { > var newObj = new Object(); > for(var e in obj) > newObj[e] = obj[e]; > return newObj; > > } > > cursor = 5; > function (__structure Glyphs_Out, __boolean Same, __string Font, > __structure Glyph) > main (__structure Glyphs_In) > { > var result = new Object(); > var glyph = new Object(); > var glyphs = new Array(); > var font = new String(); > font = "LucidaGrande"; > if (!_testMode) > { > glyphs = Glyphs_In; > glyph = copy(glyphs[cursor]); > > > // This line works: > font = glyph.Font_Name; > glyph.Font_Name = font; > glyph.Y +=0.1; > // Can't modify inputs, so you'll have to copy some other > inputs too. > //glyphs[cursor]["Y"] +=0.1; > > > result.Font = font; > result.Glyph = glyph; > result.Glyphs_Out = glyphs; > return result > } > } > > Hope that helps! :) > > -- > [ christopher wright ] > [email protected] > http://kineme.net/ > > -- > [ christopher wright ] > [email protected] > http://kineme.net/ > >
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