80 lines
2.4 KiB
Go
80 lines
2.4 KiB
Go
package arbitrary
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import "fmt"
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// Runes returns an arbitrary []rune.
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//
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// Runes accepts either zero (0), one (1) or two (2) parameters. (These parameters
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// must be specific types and have specific and different meanings.)
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//
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// So you can call it like:
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//
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// rs1 := arb.Runes()
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//
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// rs2 := arb.Runes(10) // Returns an arbitrary []rune of length 10
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//
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// rs1 := arb.Runes(10, "ABCDEF0123456789") // Returns an arbitrary []rune of length 10,
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// // with characters drawn from "ABCDEF0123456789".
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//
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// rs1 := arb.Runes(10, []rune{'a', 'b', 'c'}) // Returns an arbitrary []rune of length 10,
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// // with characters drawn from []rune{'a', 'b', 'c'}.
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//
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func (arb T) Runes(args ...interface{}) []rune {
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// For the arbitrary []rune, figure out (a) the number of runes to include and (b) which runes
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// to draw from.
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//
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// We store "the number of runes to include" in the variable "num_arbitrary_runes".
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// And we store "which runes to draw from" in the variable "runes".
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//
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// These have default values, but they can be overridden by parameters.
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var num_arbitrary_runes = 13
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var runes []rune = []rune("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz")
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switch length := len(args); length {
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case 2:
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switch t := args[1].(type) {
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case string:
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runes = []rune(t)
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case []rune:
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runes = t
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default:
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panic( fmt.Sprintf("Runes only accept a 2nd parameter to type string of type []rune. %T was passed.", args[0]) )
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}
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fallthrough
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case 1:
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switch t := args[0].(type) {
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case int:
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num_arbitrary_runes = t
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default:
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panic( fmt.Sprintf("Runes only accept a 1st parameter to type string of type int. %T was passed.", args[0]) )
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}
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case 0:
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// Nothing here.
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default:
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panic( fmt.Sprintf("Runes only accepts zero (0) or one (1) parameters. %d was passed.", length) )
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}
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// Short circuit.
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//
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// If the "num_arbitrary_runes" is zero (0), then there is
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// no point executing the rest of the code.
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if 1 > num_arbitrary_runes {
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/////////////////////// RETURN
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return []rune{}
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}
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// Construct the arbitrary []rune.
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arbitrary_runes := make([]rune, num_arbitrary_runes)
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l := len(runes)
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for i,_ := range arbitrary_runes {
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arbitrary_runes[i] = runes[arb.randomness.Intn(l)]
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}
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// Return.
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return arbitrary_runes
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}
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