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→Making tags
Miraheze>Adám Brudzewsky |
Miraheze>Adám Brudzewsky |
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</source> | </source> | ||
=== Making <code><circle/></code> tags === | === Making <code><circle/></code> tags === | ||
To help us create our SVG <code><circle/></code> tags, well set up a couple of helper functions. The first function will help us create tag attributes. | |||
==== Formatting attributes ==== | |||
APL uses a [[high minus]] (<source lang=apl inline>¯</source>), to indicate that a number is negative. This avoids confusion with the [[negate]] function <source lang=apl inline>-</source>. However, SVG uses a regular dash, so we need to change our numeric arrays into character representations (using the [[format]] function, <source lang=apl inline>⍕</source>), and [[replace]] all occurrences of the symbol: | |||
<source lang=apl> | |||
'¯'⎕R'-'⍕3 ¯1 2 ¯7 | |||
3 -1 2 -7 | |||
</source> | |||
The attribute value needs to be quoted, so we [[concatenate|prepend]] (<source lang=apl inline>,</source>) two quotation marks, and then we [[rotate]] the text one step (left), thereby pushing the first one to the end: | |||
<source lang=apl> | |||
1⌽'""','¯'⎕R'-'⍕3 ¯1 2 ¯7 | |||
"3 -1 2 -7" | |||
</source> | |||
Finally, create the full attribute phrase: | |||
<source lang=apl> | |||
' ','test','=',1⌽'""','¯'⎕R'-'⍕3 ¯1 2 ¯7 | |||
test="3 -1 2 -7" | |||
</source> | |||
==== Our first function ==== | |||
In the most basic form, a [[dfn]] ("dee fun") is just an expression in curly braces with <source lang=apl inline>⍺</source> and <source lang=apl inline>⍵</source> representing the left and right arguments, just like they are the leftmost and rightmost letters of the [[wikipedia:Greek alphabet]]: | |||
<source lang=apl> | |||
Attr←{' ',⍺,'=',1⌽'""','¯'⎕R'-'⍕⍵} | |||
'test' Attr 3 ¯1 2 ¯7 | |||
test="3 -1 2 -7" | |||
</source> | |||
Notice that assignment works for functions too! Remember the [[#Automatic_mapping|automatic mapping]]? It doesn't apply to user-defined functions, but we can use the [[Each]] operator (<source lang=apl inline>¨</source>) instead: | |||
<source lang=apl> | |||
'test' 'foo' Attr¨ 3 ¯1 | |||
┌─────────┬─────────┐ | |||
│ test="3"│ foo="-1"│ | |||
└─────────┴─────────┘ | |||
</source> | |||
==== Flattening ==== | |||
Next, we make this list of strings (each of which is actually just a character list) into a simple list with the [[enlist]] function (<source lang=apl inline>∊</source>), and use above same concatenation and rotation techniques to finalise our tag: | |||
<source lang=apl> | |||
2⌽'/><tag',∊'test' 'foo'Attr¨ 3 ¯1 | |||
<tag test="3" foo="-1"/> | |||
</source> | |||
Let's create a dfn for that too: | |||
<source lang=apl> | |||
Circle←{⊂2⌽'/><circle',∊'cx' 'cy' 'r'Attr¨⍵} | |||
Circle 3 1 4 | |||
┌─────────────────────────────┐ | |||
│<circle cx="3" cy="1" r="4"/>│ | |||
└─────────────────────────────┘ | |||
</source> | |||
Notice that a put in <source lang=apl inline>⊂</source>) which [[enclose]]s the result. This is because I want to deal with these tags a [[scalar]] elements. | |||
<source lang=apl> | <source lang=apl> | ||
</source> | </source> | ||
<source lang=apl> | <source lang=apl> | ||
</source> | </source> | ||
<source lang=apl> | <source lang=apl> | ||
</source> | </source> | ||