40 lines
1.6 KiB
Markdown
40 lines
1.6 KiB
Markdown
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# Making a cow function
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The original cowsay used Perl scripts (called 'cowfiles') to allow for creating more ASCII
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cow art. Cowsay.jl uses Julia functions, instead. In order to be usable by `Cowsay.cowsay`,
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a cow function **must**
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1. Take the correct arguments
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The function must take three (3)
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[keyword arguments](https://docs.julialang.org/en/v1/manual/functions/#Keyword-Arguments)
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of the form
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- `eyes::AbstractString="oo"`
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- `tongue::AbstractString=" "`
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- `thoughts::AbstractString="\\"`
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When drawing the cow artwork, you may then use the variables `eyes` in place of the
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eyes, `tongue` in place of the tongue, and `thoughts` in place of the speech ballon
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trail. Use of these variables in constructing the cow is optional (but makes the use of
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your cow function far more fun), but all three arguments must be present in the
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signature, regardless.
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2. Return a string
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The cow artwork must be returned from the function as a string. This is distinctly
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different from how the original cowsay modified the `$the_cow` variable.
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## Helpful hints for making cow functions
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1. Include one function per file, with the extension `.cow.jl`
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2. Do not indent within a `.cow.jl` file to better see the artwork
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3. Make use of string literals (`"""`) and string interpolation (`$`) to build the cow
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art
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4. Be sure to escape backslashes (`\`) and dollar signs (`$`) within your artwork
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5. When converting from Perl cowfiles, _unescape_ at symbols (`@`), as these are
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**not** special in Julia strings
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6. Split the `eyes` variable to get individual left- and right-eye when creating large cow
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functions
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7. Have fun!
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