Clarion Date Regex Matcher - Extract Dates from Text

Content is user-generated and unverified.
PROGRAM

  MAP
    MODULE('API')
      MatchDatePattern(STRING pText), BOOL, PASCAL
      ExtractDateFromText(STRING pText), STRING, PASCAL
    END
  END

MatchDatePattern PROCEDURE(STRING pText)
Months    STRING('January|February|March|April|May|June|July|August|September|October|November|December|' & |
                 'Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec')
MonthAbbr STRING('Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec')
Result    BOOL(FALSE)
Pos       LONG
TextLen   LONG
i         LONG
j         LONG
Word      STRING(20)
Day       STRING(10)
Year      STRING(10)
InWord    BOOL
FoundMonth BOOL
FoundDay   BOOL
FoundYear  BOOL
DayNum    LONG

  CODE
  TextLen = LEN(CLIP(pText))
  Pos = 1
  
  ! Loop through the text looking for date patterns
  LOOP WHILE Pos <= TextLen
    FoundMonth = FALSE
    FoundDay = FALSE
    FoundYear = FALSE
    Word = ''
    
    ! Skip leading whitespace
    LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
      Pos += 1
    END
    
    IF Pos > TextLen THEN BREAK.
    
    ! Try to match a month name
    i = Pos
    LOOP WHILE i <= TextLen AND (pText[i] >= 'A' AND pText[i] <= 'Z' OR pText[i] >= 'a' AND pText[i] <= 'z')
      Word = CLIP(Word) & pText[i]
      i += 1
    END
    
    ! Check if Word is a valid month
    IF INSTRING(UPPER(CLIP(Word)), 'JANUARY|FEBRUARY|MARCH|APRIL|MAY|JUNE|JULY|AUGUST|SEPTEMBER|OCTOBER|NOVEMBER|DECEMBER|' & |
                'JAN|FEB|MAR|APR|JUN|JUL|AUG|SEP|OCT|NOV|DEC', 1, 1)
      FoundMonth = TRUE
      Pos = i
      
      ! Skip whitespace after month
      LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
        Pos += 1
      END
      
      ! Try to match day (1-2 digits)
      Day = ''
      LOOP WHILE Pos <= TextLen AND (pText[Pos] >= '0' AND pText[Pos] <= '9') AND LEN(CLIP(Day)) < 2
        Day = CLIP(Day) & pText[Pos]
        Pos += 1
      END
      
      IF LEN(CLIP(Day)) > 0
        DayNum = Day
        IF DayNum >= 1 AND DayNum <= 31
          FoundDay = TRUE
          
          ! Skip optional ordinal suffix (st, nd, rd, th)
          IF Pos + 1 <= TextLen
            IF (pText[Pos] = 's' AND pText[Pos+1] = 't') OR |
               (pText[Pos] = 'n' AND pText[Pos+1] = 'd') OR |
               (pText[Pos] = 'r' AND pText[Pos+1] = 'd') OR |
               (pText[Pos] = 't' AND pText[Pos+1] = 'h')
              Pos += 2
            END
          END
          
          ! Skip optional comma
          IF Pos <= TextLen AND pText[Pos] = ','
            Pos += 1
          END
          
          ! Skip whitespace
          LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
            Pos += 1
          END
          
          ! Try to match 4-digit year
          Year = ''
          LOOP WHILE Pos <= TextLen AND (pText[Pos] >= '0' AND pText[Pos] <= '9') AND LEN(CLIP(Year)) < 4
            Year = CLIP(Year) & pText[Pos]
            Pos += 1
          END
          
          IF LEN(CLIP(Year)) = 4
            FoundYear = TRUE
          END
        END
      END
    ELSE
      Pos += 1
    END
    
    IF FoundMonth AND FoundDay AND FoundYear
      Result = TRUE
      BREAK
    END
  END
  
  RETURN Result

ExtractDateFromText PROCEDURE(STRING pText)
Result    STRING(50)
Pos       LONG
TextLen   LONG
i         LONG
Word      STRING(20)
Day       STRING(10)
Year      STRING(10)
FoundMonth BOOL
FoundDay   BOOL
FoundYear  BOOL
DayNum    LONG
DateStart LONG

  CODE
  Result = ''
  TextLen = LEN(CLIP(pText))
  Pos = 1
  
  LOOP WHILE Pos <= TextLen
    FoundMonth = FALSE
    FoundDay = FALSE
    FoundYear = FALSE
    Word = ''
    DateStart = Pos
    
    ! Skip leading whitespace
    LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
      Pos += 1
      DateStart = Pos
    END
    
    IF Pos > TextLen THEN BREAK.
    
    ! Try to match a month name
    i = Pos
    LOOP WHILE i <= TextLen AND (pText[i] >= 'A' AND pText[i] <= 'Z' OR pText[i] >= 'a' AND pText[i] <= 'z')
      Word = CLIP(Word) & pText[i]
      i += 1
    END
    
    ! Check if Word is a valid month
    IF INSTRING(UPPER(CLIP(Word)), 'JANUARY|FEBRUARY|MARCH|APRIL|MAY|JUNE|JULY|AUGUST|SEPTEMBER|OCTOBER|NOVEMBER|DECEMBER|' & |
                'JAN|FEB|MAR|APR|JUN|JUL|AUG|SEP|OCT|NOV|DEC', 1, 1)
      FoundMonth = TRUE
      Pos = i
      
      ! Skip whitespace after month
      LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
        Pos += 1
      END
      
      ! Try to match day
      Day = ''
      LOOP WHILE Pos <= TextLen AND (pText[Pos] >= '0' AND pText[Pos] <= '9') AND LEN(CLIP(Day)) < 2
        Day = CLIP(Day) & pText[Pos]
        Pos += 1
      END
      
      IF LEN(CLIP(Day)) > 0
        DayNum = Day
        IF DayNum >= 1 AND DayNum <= 31
          FoundDay = TRUE
          
          ! Skip optional ordinal suffix
          IF Pos + 1 <= TextLen
            IF (pText[Pos] = 's' AND pText[Pos+1] = 't') OR |
               (pText[Pos] = 'n' AND pText[Pos+1] = 'd') OR |
               (pText[Pos] = 'r' AND pText[Pos+1] = 'd') OR |
               (pText[Pos] = 't' AND pText[Pos+1] = 'h')
              Pos += 2
            END
          END
          
          ! Skip optional comma
          IF Pos <= TextLen AND pText[Pos] = ','
            Pos += 1
          END
          
          ! Skip whitespace
          LOOP WHILE Pos <= TextLen AND pText[Pos] = ' '
            Pos += 1
          END
          
          ! Try to match 4-digit year
          Year = ''
          LOOP WHILE Pos <= TextLen AND (pText[Pos] >= '0' AND pText[Pos] <= '9') AND LEN(CLIP(Year)) < 4
            Year = CLIP(Year) & pText[Pos]
            Pos += 1
          END
          
          IF LEN(CLIP(Year)) = 4
            FoundYear = TRUE
          END
        END
      END
    ELSE
      Pos += 1
    END
    
    IF FoundMonth AND FoundDay AND FoundYear
      Result = SUB(pText, DateStart, Pos - DateStart)
      BREAK
    END
  END
  
  RETURN Result
Content is user-generated and unverified.