pattern_value_result_invalid

A (pure …) expression evaluated but produced a value no hap can carry.

The cycle-0 dry-run of a (pure …) expression leaf succeeded, but its result is a form, a vector, a date, or a time, none of which a hap value can be (a hap carries a symbol / string / keyword / number / boolean / nil). The most common cause is a misspelled function name: an unresolved head does not error, it evaluates to a form literal (SJON’s form-construction semantics), which then fails this shape check. The leaf degrades to silence. Fix the name, or have the expression reduce to a scalar.

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Run sjon explain pattern_value_result_invalid to read this at a terminal, browse every code, or work through diagnostics-driven repair if you want the habit rather than the answer.