Conditional Expressions

Bisql supports a small expression language inside if and elseif directives.

The goal is to keep conditional SQL readable without turning SQL templates into a general-purpose scripting language.

Supported Operators

Bisql currently supports:

• logical operators: and, or
• comparison operators: =, !=, <, <=, >, >=
• parentheses: (, )

Examples:

/*%if active and status = expected_status */
  status = 'pending'
/*%end */

/*%if (active and status = expected_status) or pending */
  status = 'pending'
/*%end */

Operands

Operands are parameter references.

That means both sides of a comparison are resolved from the params map:

/*%if status = expected_status */

{:status "pending"
 :expected_status "pending"}

Dot-path access also works:

/*%if user.id = owner.id */

{:user {:id 10}
 :owner {:id 10}}

A bare identifier is treated as a truthiness check:

/*%if active */

Operator Precedence

Expressions follow this precedence order:

1. comparison operators
2. and
3. or

So this:

/*%if active or status = expected_status and pending */

is interpreted as:

active or ((status = expected_status) and pending)

Use parentheses when you want a different grouping.

Current Limitations

The initial expression language is intentionally small.

These are not supported yet:

• not
• string, number, boolean, or nil literals
• arithmetic operators
• function calls

For example, this is not supported:

/*%if status = "active" */

Instead, compare parameters:

/*%if status = expected_status */

{:status "active"
 :expected_status "active"}

See also:

• SQL Rendering
• Rendering Examples