Guest User

Untitled

a guest
Feb 1st, 2012
71
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. expr = expr + ident // r1
  2. | ident // r2
  3.  
  4. | ident | + | $ | expr |
  5. 0 | s1 | | | 2 |
  6. 1 | r2 | r2 | r2| |
  7. 2 | | s3 |acc| |
  8. 3 | s4 | | | 2 |
  9. 4 | r1 | r1 | r1| |
  10.  
  11. struct result {
  12. symbol nonterm;
  13. int tokens_to_reduce;
  14. }
  15.  
  16. result state0(token* stream) {
  17. result res;
  18. switch(stream[0]) {
  19. case ident:
  20. res = state1(stream+1);
  21. break;
  22. default: throw error();
  23. }
  24. while(true) {
  25. if(res.tokens_to_reduce == 0) {
  26. switch(res.nonterm) {
  27. case expr:
  28. res = state2(stream);
  29. break;
  30. default: throw error();
  31. }
  32. }
  33. else return { res.non_term, res.tokens_to_reduce-1 };
  34. }
  35. }
  36.  
  37. result state1(token* stream) {
  38. reduce2(); // needs arguments
  39. return { expr, 0 };
  40. }
  41.  
  42. result state2(token* stream) {
  43. result res;
  44. switch(stream[0]) {
  45. case plus:
  46. res = state3(stream+1);
  47. break;
  48. case end:
  49. return accept(); // needs some work
  50. default: throw error();
  51. }
  52. }
  53.  
  54. result state3(token* stream) {
  55. result res;
  56. switch(stream[0]) {
  57. case ident:
  58. res = state4(stream+1);
  59. break;
  60. default: throw error();
  61. }
  62. while(true) {
  63. if(res.tokens_to_reduce == 0) {
  64. switch(res.nonterm) {
  65. case expr:
  66. res = state2(stream);
  67. break;
  68. default: throw error();
  69. }
  70. }
  71. else return { res.non_term, res.tokens_to_reduce-1 };
  72. }
  73. }
  74.  
  75. result state4(token* stream) {
  76. reduce1(); // needs arguments
  77. return { expr, 1 };
  78. }
RAW Paste Data

Adblocker detected! Please consider disabling it...

We've detected AdBlock Plus or some other adblocking software preventing Pastebin.com from fully loading.

We don't have any obnoxious sound, or popup ads, we actively block these annoying types of ads!

Please add Pastebin.com to your ad blocker whitelist or disable your adblocking software.

×