generator

Documentation

Overview

generator provides low level structures and functions used to efficiently generate strings from a regex pattern

Example (IncSplitConcat)

// this is not an actual example, but an internal test.

lls := [][]int{
	{0, 0, 4},
	{0, 3},
	{2},
	{},
	{0, 0, 0, 1},
}

for _, ll := range lls {
	n := sum(ll)
	var err error
	fmt.Println()
	fmt.Println(ll) // initial value
	for err == nil {
		err = incSplitConcat(ll)
		if n != sum(ll) {
			panic("incSplitConcat changed the sum of the split")
		}
		fmt.Println(ll, err)
	}
}

Output:


[0 0 4]
[1 0 3] <nil>
[2 0 2] <nil>
[3 0 1] <nil>
[4 0 0] <nil>
[0 1 3] <nil>
[1 1 2] <nil>
[2 1 1] <nil>
[3 1 0] <nil>
[0 2 2] <nil>
[1 2 1] <nil>
[2 2 0] <nil>
[0 3 1] <nil>
[1 3 0] <nil>
[0 4 0] <nil>
[0 0 4] done

[0 3]
[1 2] <nil>
[2 1] <nil>
[3 0] <nil>
[0 3] done

[2]
[2] done

[]
[] done

[0 0 0 1]
[1 0 0 0] <nil>
[0 1 0 0] <nil>
[0 0 1 0] <nil>
[0 0 0 1] done

Example (IncSplitStar)

// this is not an actual example, but an internal test.

ss := [][]int{
	{4},
	{},
	{1},
}
for _, s := range ss {
	var err error
	fmt.Println("\nStarting with ", s)
	for err == nil {
		s, err = incSplitStar(s)
		fmt.Println(s, err)
	}
}

Output:

Starting with  [4]
[3 1] <nil>
[2 2] <nil>
[2 1 1] <nil>
[1 3] <nil>
[1 2 1] <nil>
[1 1 2] <nil>
[1 1 1 1] <nil>
[] done

Starting with  []
[] done

Starting with  [1]
[] done

Index

• Variables
• type Generator
  • func NewGenerator(ctx context.Context, pattern string, max int) (Generator, error)

Examples

• Package (IncSplitConcat)
• Package (IncSplitStar)

Variables

var ErrDone = fmt.Errorf("done")

Types

type Generator

type Generator interface {

	// Sould be called before next is called.
	// Error only on irrecoverable errors.
	// Never error if nothing can be generated.
	Reset(length int) error

	// Generate next string
	// Returns error if no more string available.
	Next() error

	// Retrieve the last generated string.
	// May be called multiple times, and will always
	// return the same result until Next() is called again.
	// Undefined if called before Next() is called.
	Last() string
}

func NewGenerator

func NewGenerator(ctx context.Context, pattern string, max int) (Generator, error)

Compile a pattern into a new Generator. You must provide a maximum length (ie, capacity) for further resets. The new generator has to be reset to the target length(less or equal to max) before Next() can be called and Last() can be read.