Tcl

Regular Expression with Multiple Matches and Named Capture Groups

See more Regular Expressions Examples

Demonstrates regular expressions with named capture groups and multiple matches. Tcl

load ./chilkat.dll

set success 0

set sb [new_CkStringBuilder]

set crlf 1
CkStringBuilder_AppendLine $sb "Name: John Smith" $crlf
CkStringBuilder_AppendLine $sb "Name: Jack Johnson" $crlf
CkStringBuilder_AppendLine $sb "Name: Mary Adams" $crlf

puts [CkStringBuilder_getAsString $sb]

# We have the following string:
# Name: John Smith
# Name: Jack Johnson
# Name: Mary Adams

set pattern "Name:\\s+(?<first>\\w+)\\s+(?<last>\\w+)"
set json [new_CkJsonObject]

CkJsonObject_put_EmitCompact $json 0

set timeoutMs 2000
set numMatches [CkStringBuilder_RegexMatch $sb $pattern $json $timeoutMs]
if {$numMatches < 0} then {
    # Probably an error in the regular expression.
    # Suggestion: Use AI to help create and/or diagnose regular expressions.
    puts [CkStringBuilder_lastErrorText $sb]
    delete_CkStringBuilder $sb
    delete_CkJsonObject $json
    exit
}

# Examine the matches:
puts [CkJsonObject_emit $json]

# Here is the JSON showing the matches.
# Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

# {
#   "named": {
#     "first": 1,
#     "last": 2
#   },
#   "match": [
#     {
#       "group": [
#         {
#           "cap": "Name: John Smith",
#           "idx": 0,
#           "len": 16
#         },
#         {
#           "cap": "John",
#           "idx": 6,
#           "len": 4
#         },
#         {
#           "cap": "Smith",
#           "idx": 11,
#           "len": 5
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Jack Johnson",
#           "idx": 18,
#           "len": 18
#         },
#         {
#           "cap": "Jack",
#           "idx": 24,
#           "len": 4
#         },
#         {
#           "cap": "Johnson",
#           "idx": 29,
#           "len": 7
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Mary Adams",
#           "idx": 38,
#           "len": 16
#         },
#         {
#           "cap": "Mary",
#           "idx": 44,
#           "len": 4
#         },
#         {
#           "cap": "Adams",
#           "idx": 49,
#           "len": 5
#         }
#       ]
#     }
#   ]
# }

# The capture group index is obtained by looking up the name in the JSON result.
# For example:

set idx_first [CkJsonObject_IntOf $json "named.first"]
set idx_last [CkJsonObject_IntOf $json "named.last"]

set i 0
set matchCount [CkJsonObject_SizeOfArray $json "match"]
while {$i < $matchCount} {
    puts "Match [expr $i + 1]:"
    CkJsonObject_put_I $json $i

    CkJsonObject_put_J $json $idx_first
    puts "first: [CkJsonObject_stringOf $json {match[i].group[j].cap}]"

    CkJsonObject_put_J $json $idx_last
    puts "first: [CkJsonObject_stringOf $json {match[i].group[j].cap}]"

    puts 
    set i [expr $i + 1]
}

# Output is: 

# Match 1:
# first: John
# first: Smith
# 
# Match 2:
# first: Jack
# first: Johnson
# 
# Match 3:
# first: Mary
# first: Adams

delete_CkStringBuilder $sb
delete_CkJsonObject $json