expressions.dtd

<!-- DTD for libexpr Expression XML Format -->
<!-- This DTD defines the structure for arithmetic and boolean expressions -->

<!-- Root element containing multiple expressions -->
<!ELEMENT expressions (expression*)>

<!-- Individual expression with optional name and description -->
<!ELEMENT expression (operation)>
<!ATTLIST expression
    name        CDATA   #IMPLIED
    description CDATA   #IMPLIED>

<!-- Operation element containing operands -->
<!ELEMENT operation (operand | operation)*>
<!ATTLIST operation
    type        (SUM|SUB|MUL|DIV|MOD|
                 EQ|NE|GT|GE|LT|LE|
                 AND|OR|XOR|NOT|
                 ABS|SIN|COS|TAN|
                 ASIN|ACOS|ATAN|
                 TEST|CHANGE) #REQUIRED>

<!-- Operand element with typed value -->
<!ELEMENT operand (#PCDATA)>
<!ATTLIST operand
    type        (integer|float|string) #REQUIRED>