Precedence Indices

The grammar provides a standard sequence of precedence indices. Grammar rules for expressions generally look like this:

x[s_term_pri] := x[s_term_pri] "/" x[>s_term_pri] =># '(Infix)';

The name x is used for expressions, the precedence index is a special modifier on the LHS of the production. In the middle part, x[s_term_pri] means any expression with the same precedence or higher, whilst x[>s_term_pri] means any expression with a strictly higher precedence. Thus, this means the division operator / is left associative.

On the other hand:

x[sdollar_apply_pri] := x[>sdollar_apply_pri] "$" x[sdollar_apply_pri] =>#
  "`(ast_apply ,_sr (,_1 ,_3))"
;

which means the Haskell $ application operator is right associative.

Here is the precedence specification from the grammar:

priority
  let_pri <
  slambda_pri <

  // low precedence applications
  spipe_apply_pri <
  sdollar_apply_pri <

  // tuples
  stuple_cons_pri <
  stuple_pri <

  // basic logic
  simplies_condition_pri <
  sor_condition_pri <
  sand_condition_pri <
  snot_condition_pri <


  // TeX symbol logic
  stex_implies_condition_pri <
  stex_or_condition_pri <
  stex_and_condition_pri <
  stex_not_condition_pri <

  scomparison_pri <
  sas_expr_pri <

  // set operators
  ssetunion_pri <
  ssetintersection_pri <

  // arrow types
  sarrow_pri <

  // constructor forms
  scase_literal_pri <

  // bitwise operators
  sbor_pri <
  sbxor_pri <
  sband_pri <
  sshift_pri <

  // numeric operators
  ssum_pri <
  ssubtraction_pri <
  sproduct_pri <
  s_term_pri <
  sprefixed_pri <
  spower_pri <
  ssuperscript_pri <

  // addression operations
  srefr_pri <
  scoercion_pri <

  // high precedence applications
  sapplication_pri <

  sfactor_pri <
  srcompose_pri <
  sthename_pri <

  // atomic forms
  satomic_pri
;