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diff --git a/docs/chapter17b/17-grammar.md b/docs/chapter17b/17-grammar.md new file mode 100644 index 00000000..9a70f323 --- /dev/null +++ b/docs/chapter17b/17-grammar.md @@ -0,0 +1,22 @@ +# Chapter 17b grammar additions + +Start with [Chapter 17a's declaration syntax](../../chapter17a/docs/17-grammar.md). +This chapter adds inference, assignment shortcuts, conditional expressions, and +`for` loops. Access and binding permissions keep the same meaning. + +```text +inferredDeclaration = ("var" | "val") ("!" | "~")? identifier "=" assignment +assignment = expression (assignmentOperator assignment)? +assignmentOperator = "=" | "+=" | "-=" | "*=" | "/=" | "&=" | "|=" | "^=" + | "<<=" | ">>=" | ">>>=" +expression = bitwise ("?" assignment (":" assignment)?)? +prefixUpdate = ("++" | "--") identifier +postfixUpdate = lvalue ("++" | "--") +forStatement = "for" "(" declarationOrExpression? ";" assignment? ";" + assignment? ")" statement +``` + +Declarations can contain several comma-separated names. `var` permits +reassignment and `val` fixes the binding; both retain the initializer's reference +permissions. Postfix updates also support fields and array elements. Prefix +updates currently support local names. See the README for evaluation order. |