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Version: 2.0

Conditional Logic

CISIS allows complex decision-making within the format using the if structure. This is essential for hiding labels of missing fields or changing formatting based on content (e.g., "If book is restricted, show Red text").

The IF Command​

  • Syntax:
if <condition> then <commands> else <commands> fi

  • Note: The else part is optional. The fi (end if) is mandatory.

Checking Field Presence​

The most common conditions check if a field exists (p) or is absent (a).

  • p(vTag): True if the field is Present.
  • a(vTag): True if the field is Absent (Empty).

Example:

if p(v10) then "Author: ", v10 else "Anonymous" fi

Comparing Values​

You can compare fields against text strings or other fields.

  • Operators: =, <> (Not equal), >, <, >=, <=
  • Numeric Comparison: To compare numbers, use val() to convert the string to a number. if val(v20) > 2000...

Example:

if v20:'1999' then 'Published in 1999' fi

Logical Operators​

Combine multiple conditions.

  • AND: Both must be true.
  • OR: At least one must be true.
  • NOT: Inverts the result.

Example:

if p(v10) AND a(v20) then 'Author present, but no Year' fi