Invalid Formula Operator

This message appears when a formula (a value that starts with =) uses an operator TradersPost explicitly disallows:

• ** — exponentiation (use repeated * instead if you need a power)
• .. — ranges
• matches — regular-expression matching

Those three operators are rejected for this error. Prefer these operators instead:

• Arithmetic: +, -, *, /, % (modulo)
• Comparison: ==, !=, <, >, <=, >=
• Logical: and, or, not (and && / || where applicable)
• Ternary: ?:
• String concatenation: ~
• Containment: in, not in
• References: payload values as signal.<topLevelKey> (for example signal.limitPrice)

Other expression forms may still parse without triggering this message. Syntax and reference problems use different codes (see invalid formula syntax and invalid formula reference).

Invalid examples (these use a disallowed operator):

{
  "ticker": "SPY",
  "action": "buy",
  "x": "=2 ** 10"
}

{
  "ticker": "SPY",
  "action": "buy",
  "x": "=1..5"
}

{
  "ticker": "SPY",
  "action": "buy",
  "symbol": "SPY",
  "x": "=signal.symbol matches \"/SPY/\""
}

Valid examples using allowed operators:

{
  "ticker": "SPY",
  "action": "buy",
  "x": "=signal.ticker == \"SPY\""
}

{
  "ticker": "SPY",
  "action": "buy",
  "closePrice": "450.25",
  "limitPrice": "=signal.closePrice + 0.5"
}

{
  "ticker": "SPY",
  "action": "buy",
  "venue": "NYSE",
  "x": "=signal.venue in [\"NYSE\", \"AMEX\"]"
}

For where = is permitted on the payload, see invalid formula syntax.