slideshow/source/engine/arith-grammar.txt

   1 Based on the C grammar for arithmetic expressions
   2 =================================================
   3
   4 number_digit = '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9'
   5
   6 number_exponent = 'e'|'E'
   7
   8 basic_number = basic_number number_digit | number_digit
   9
  10 number =
  11            basic_number |
  12
  13            basic_number number_exponent basic_number |
  14            basic_number number_exponent '-' basic_number |
  15            basic_number number_exponent '+' basic_number |
  16
  17            '.' basic_number number_exponent basic_number |
  18            '.' basic_number number_exponent '-' basic_number |
  19            '.' basic_number number_exponent '+' basic_number |
  20
  21            basic_number '.' number_exponent basic_number |
  22            basic_number '.' number_exponent '-' basic_number |
  23            basic_number '.' number_exponent '+' basic_number |
  24
  25            basic_number '.' basic_number number_exponent basic_number |
  26            basic_number '.' basic_number number_exponent '-' basic_number |
  27            basic_number '.' basic_number number_exponent '+' basic_number
  28
  29
  30 identifier = '$'|'pi'|'e'|'X'|'Y'|'Width'|'Height'
  31               ^            ^   ^     ^       ^
  32               |            |   |     |       |
  33          '$' in PPT            |   |     |       |
  34                          '#ppt_x' in PPT   |     |       |
  35                              '#ppt_y' in PPT     |       |
  36                                        '#ppt_w' in PPT       |
  37                                '#ppt_h' in PPT
  38
  39 unary_function = 'abs'|'sqrt'|'sin'|'cos'|'tan'|'atan'|'acos'|'asin'|'exp'|'log'
  40 binary_function = 'min'|'max'
  41
  42
  43 basic_expression =
  44                                  number |
  45                                  identifier |
  46                                  unary_function '(' additive_expression ')' |
  47                                  binary_function '(' additive_expression ',' additive_expression ')' |
  48                                  '(' additive_expression ')'
  49
  50 unary_expression = '-' basic_expression
  51
  52 multiplicative_expression =
  53                                                   basic_expression |
  54                                                   multiplicative_expression '*' basic_expression |
  55                                                   multiplicative_expression '/' basic_expression
  56
  57 additive_expression =
  58                                         multiplicative_expression |
  59                                         additive_expression '+' multiplicative_expression |
  60                                         additive_expression '-' multiplicative_expression
  61