Fixed the incorrect behavior in findPatternMatchIndexes. It was prev…

[dapryor]

…iously removing chunks of the strings which was effect subsequent match index locations.

It also now supports regexp patterns to better match the name. Added a few test as well.

Please mark this as a hacktoberfest-accepted PR ;)

[codecov-io]

Codecov Report

Merging #31 into master will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #31   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines          121        84   -37     
=========================================
- Hits           121        84   -37     

Impacted Files	Coverage Δ
matcher.go	100.00% <100.00%> (ø)
log.go	100.00% <0.00%> (ø)
marker.go	100.00% <0.00%> (ø)
builder.go	100.00% <0.00%> (ø)

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[dapryor]

func findPatternMatchIndexes(str string, patternsToMatch []string) map[int]string {
    patternMatchIndexes := make(map[int]string)
    for _, patternToMatch := range patternsToMatch {
        for strings.Contains(str, patternToMatch) {
            matchIndex := strings.Index(str, patternToMatch)
            str = strings.Replace(str, patternToMatch, "", 1)
            patternMatchIndexes[matchIndex] = patternToMatch
        }
    }
    return patternMatchIndexes
}

this was the original block of code. It incorrectly found indexes. i.e.

input: "I scream, you all scream, we all scream for ice cream."
patterns: "scream", "ice"
Output:
2 scream
12 scream
21 scream
26 ice

It also did not support patterns like the name suggest, only strings due to this line str = strings.Replace(str, patternToMatch, "", 1) You would replace the match with an empty string so the first instance of scream would be correct, the second would be 6 spaces off, the third would be 12 spaces off This is the new block of code:

func findPatternMatchIndexes(str string, patternsToMatch []string) map[int]string {
    patternMatchIndexes := make(map[int]string)
    pattern := strings.Join(patternsToMatch , "|")
    patternRegex := regexp.MustCompile(pattern)
    indices := patternRegex.FindAllStringIndex(str, -1)
    for _, v := range(indices) {
        start, end := v[0], v[1]
        patternMatchIndexes[start] = str[start:end]
    }
    return patternMatchIndexes
}

It correctly finds the indexes: i.e.

input: "I scream, you all scream, we all scream for ice cream."
patterns: "scream", "ice"
Output:
2 scream
18 scream
33 scream
44 ice

and it also supports patterns since the new block uses regex