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Predicates Reference

This page names the language vocabulary. The currently verified local first-contract path is narrower: method labels, signed_by, any_signed, all_signed, threshold, modifies, post_to_path, has_property, state_exists, text_eq, text_contains, text_starts_with, text_ends_with, amount_in_range, num_eq, num_gt, num_gte, num_lt, num_lte, bool_true, and bool_false are enforced from replayable commit artifacts. See the standard predicate evidence matrix for the exact source of each fact.

Do not treat the future vocabulary below as runtime evidence until a validator path documents its artifact format and tests. Oracle, time, hash, and most WASM predicates are extension vocabulary in the local first-contract path, not proof that external facts were checked.

Signature Predicates​

+signed_by(/path/to/identity.id)
// Commit must be signed by this ed25519 key

+threshold("2", /signers/list)
// At least two signatures from the list required

+signed_by_n(/signers/list, n)
// At least n signatures from the list

Oracle Predicates​

+oracle_attests(/oracle.id, "condition")
// Oracle attests to a condition

+oracle_attests_fresh(/oracle.id, "condition", max_age_seconds)
// Oracle attestation within time limit

Time Predicates​

The validator does not evaluate time, hash, or wasm predicates yet. They never hold, so no commit takes a transition that needs one; see Standard Predicates.

+before(/deadlines/cutoff.datetime)
// Current time is before deadline

+after(/deadlines/start.datetime)
// Current time is after start time

Comparison Predicates​

// Numeric comparisons
+num_eq(/path/a.num, /path/b.num)     // a == b
+num_gt(/path/a.num, /path/b.num)     // a > b
+num_gte(/path/a.num, /path/b.num)    // a >= b
+num_lt(/path/a.num, /path/b.num)     // a < b
+num_lte(/path/a.num, /path/b.num)    // a <= b

// Text comparisons
+text_eq(/path/a.text, /path/b.text)
+text_contains(/path/a.text, "substring")
+text_starts_with(/path/a.text, "prefix")
+text_ends_with(/path/a.text, "suffix")

// Accepted-state numeric range
+amount_in_range(/invoice/amount.num, "10", "100")
+amount_in_range(/invoice/amount.num, /limits/min.num, /limits/max.num)

// Boolean
+bool_true(/path/flag.bool)
+bool_false(/path/flag.bool)

// Accepted-state path existence
+state_exists(/path/ready.flag)

The local validator derives state_exists from accepted-state path existence only; a path written by the same pending commit is not evidence for that commit.

The local validator derives bool_true and bool_false from accepted-state booleans only; a boolean written by the same pending commit is not evidence for that commit.

The local validator also derives num_eq, num_gt, num_gte, num_lt, and num_lte from accepted-state numbers only. The right-hand side can be a literal number or another accepted-state number path; a number written by the same pending commit is not evidence for that commit.

A number argument needs no quotes: +num_gte(/x.num, 100) is the same predicate as +num_gte(/x.num, "100"), and -3 and 0.25 work too.

A fraction such as 1/4 or 2/6 is a number argument too. One with an exact decimal is written as that decimal, so 1/4 is the same predicate as 0.25 and works under any predicate theory. Any other fraction is reduced (2/6 is 1/3) and is a number from predicate theory v4; before v4 a predicate given one never holds. 1/0 is a parse error.

From predicate theory v5 a number path can also be .rational, .integer or .natural (Path types): +num_lt(/out/i.natural, /out/pad.natural) compares two whole numbers.

The local validator derives text_eq, text_contains, text_starts_with, and text_ends_with from accepted-state strings only. text_eq can compare two accepted-state string paths or one path to a literal; the other text predicates check literal substrings. Text written by the same pending commit is not evidence for that commit.

Hash Predicates​

+hash_matches(/commitments/secret.hash, /revealed/value.text)
// SHA256 of revealed value matches stored hash

Custom WASM Predicates​

+wasm(/predicates/my_predicate.wasm, arg1, arg2)
// Call custom WASM predicate with arguments