--- title: "Disambiguating Operators" description: "A crucial aspect of the syntax is distinguishing between operators that are part of a dice modifier (acting on individual dice or the rolling process itself) and operators that initiate standard math…" canonical: "https://www.questportal.com/documentation/Lx1x0qWIA1/disambiguating-operators" section: "Documentation / Dice / Roll Formulas" source: "Quest Portal documentation" version: 237 --- # Disambiguating Operators ## Modifiers vs. Expressions A crucial aspect of the syntax is distinguishing between operators that are part of a _dice modifier_ (acting on individual dice or the rolling process itself) and operators that initiate standard _mathematical or comparison expressions_ (acting on the numeric result of the preceding component). **The Core Rule: Spaces or Parentheses Matter** The parser uses spaces and parentheses to resolve ambiguity: 1. **No Space:** An operator immediately following a roll or modifier component is typically treated as _part of that modifier_ if the syntax allows (e.g., \`k\`, \`!\`, \`r\`, \`cs\`, \`>\`, \`\<\`, \`=\`, etc.). 2. **Space(s):** An operator separated by one or more spaces from the preceding component is treated as initiating a standard mathematical or comparison expression that operates on the _result_ of the preceding component. 3. **Parentheses:** Placing parentheses around a roll expression, like \`(2d6)\`, forces the subsequent operator to be treated as a mathematical or comparison operator acting on the group's result, even without spaces (though spaces are still recommended for readability). ### **Examples of Ambiguity and Resolution** This distinction is most critical for operators like \`>\`, \`\<\`, and \`=\` which can function as both success/target conditions within modifiers AND as standard comparison operators: - **Success Modifier:** \`5d10>7\` - _Meaning:_ Roll 5d10, count dice showing 7 or higher. \`>\` is part of the success modifier. - _Example:_ Roll \`\[8, 3, 10, 7, 4\]\` -> \`3\` successes. - **Comparison Expression:** \`5d10 > 7\` or \`(5d10)>7\` - _Meaning:_ Roll 5d10, sum the results, then check if the total is greater than 7. Returns \`1\` (true) or \`0\` (false). - _Example:_ Roll \`\[4, 2, 1, 5, 3\]\` -> Total \`15\`. \`15 > 7\` is true. -> Result \`1\`. The same principle applies when these operators follow other modifiers: - **Explode Target:** \`3d6!>5\` - _Meaning:_ Roll 3d6, explode dice showing 5 or 6. \`>5\` sets the explode target. - _Example:_ Roll \`\[5, 2, 6\]\` -> Explode 5 (roll 3), Explode 6 (roll 1) -> Pool \`\[5, 2, 6, 3, 1\]\`, Total \`17\`. - **Explode + Comparison:** \`3d6! > 5\` or \`(3d6!) > 5\` - _Meaning:_ Roll 3d6, explode only dice showing 6 (default \`!\` target), sum the result, then check if the total is greater than 5. - _Example:_ Roll \`\[5, 2, 6\]\` -> Explode 6 (roll 1) -> Pool \`\[5, 2, 6, 1\]\`, Total \`14\`. \`14 > 5\` is true. -> Result \`1\`. - **Reroll Target:** \`4d6r=1\` - _Meaning:_ Roll 4d6, reroll any dice showing exactly 1. \`=1\` sets the reroll target. - _Example:_ Roll \`\[1, 4, 1, 6\]\` -> Reroll 1 (gets 3), Reroll 1 (gets 5) -> Pool \`\[3, 4, 5, 6\]\`, Total \`18\`. - **Reroll + Comparison:** \`4d6r = 1\` or \`(4d6r) = 1\` - _Meaning:_ Roll 4d6, reroll any dice showing exactly 1 (default \`r\` target), sum the result, then check if the total equals 1. - _Example:_ Roll \`\[1, 4, 1, 6\]\` -> Pool \`\[3, 4, 5, 6\]\`, Total \`18\`. \`18 = 1\` is false. -> Result \`0\`. **Standard Math Operators (\`+\`, \`-\`, \`\*\`, \`/\`, etc.)** For operators like \`+\`, \`-\`, \`\*\`, \`/\`, the presence or absence of spaces is crucial for meaning, especially when they follow modifiers that can take numeric arguments. - **Modifier Argument:** \`3d6k+1\` - _Meaning:_ Keep highest \`+1\` dice. The \`+1\` is interpreted as a signed integer argument for the \`k\` modifier because it immediately follows \`k\` without a space. - _Example:_ Roll \`\[5, 2, 6\]\` -> Keep highest 1 -> Result \`6\`. - **Mathematical Operation:** \`3d6k + 1\` - _Meaning:_ Keep highest 1 (default for \`k\`), then add 1 to the result. The space separates the \`k\` modifier (which takes its default argument) from the \`+\` mathematical operator. - _Example:_ Roll \`\[5, 2, 6\]\` -> Keep highest 1 -> \`6\`. Then \`6 + 1\` -> Result \`7\`. **Similarly** - **Modifier Argument:** \`3d6k-1\` - _Meaning:_ Keep highest \`-1\` dice. The \`-1\` is the argument for \`k\`. The implementation ensures at least 0 dice are kept, so this results in keeping 0 dice. - _Example:_ Roll \`\[5, 2, 6\]\` -> Keep highest -1 -> All dice dropped -> Result \`0\`. _This is a good example of potentially unexpected behavior: because "keep -1 dice" is semantically nonsensical, one might intuitively assume the \`-\` must be a mathematical operation. However, the parser strictly follows the grammar, interpreting the signed number \`-1\` as the modifier's argument due to the lack of space._ - **Mathematical Operation:** \`3d6k - 1\` - _Meaning:_ Keep highest 1, then subtract 1 from the result. - _Example:_ Roll \`\[5, 2, 6\]\` -> Keep highest 1 -> \`6\`. Then \`6 - 1\` -> Result \`5\`. While \`1d6+1\` vs \`1d6 + 1\` might parse identically (as the \`+\` cannot be part of the \`d6\` roll itself), ambiguity arises with modifiers like \`k\` or \`d\`. Therefore, **always using spaces around mathematical and comparison operators is strongly recommended** to make the formula's intent clear and prevent misinterpretation. **Conclusion:** Use spaces or parentheses deliberately to separate mathematical/comparison expressions from dice rolls and modifiers. When an operator _should_ be part of a modifier (like setting a target), do _not_ use spaces. --- Part of the [Quest Portal documentation](https://www.questportal.com/documentation.md) (Documentation / Dice / Roll Formulas). HTML version: .