Jeremy Hylton | 4db62b1 | 2001-02-27 19:07:02 +0000 | [diff] [blame^] | 1 | #include "Python.h" |
| 2 | #include "node.h" |
| 3 | #include "token.h" |
| 4 | #include "graminit.h" |
| 5 | #include "compile.h" |
| 6 | #include "symtable.h" |
| 7 | |
| 8 | #define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined" |
| 9 | |
| 10 | static int |
| 11 | future_check_features(PyFutureFeatures *ff, node *n) |
| 12 | { |
| 13 | int i; |
| 14 | char *feature; |
| 15 | |
| 16 | REQ(n, import_stmt); /* must by from __future__ import ... */ |
| 17 | |
| 18 | for (i = 3; i < NCH(n); ++i) { |
| 19 | feature = STR(CHILD(CHILD(n, i), 0)); |
| 20 | if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) { |
| 21 | ff->ff_nested_scopes = 1; |
| 22 | } else { |
| 23 | PyErr_Format(PyExc_SyntaxError, |
| 24 | UNDEFINED_FUTURE_FEATURE, feature); |
| 25 | return -1; |
| 26 | } |
| 27 | } |
| 28 | return 0; |
| 29 | } |
| 30 | |
| 31 | /* Relevant portions of the grammar: |
| 32 | |
| 33 | single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE |
| 34 | file_input: (NEWLINE | stmt)* ENDMARKER |
| 35 | stmt: simple_stmt | compound_stmt |
| 36 | simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE |
| 37 | small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | exec_stmt | assert_stmt |
| 38 | import_stmt: 'import' dotted_as_name (',' dotted_as_name)* | 'from' dotted_name 'import' ('*' | import_as_name (',' import_as_name)*) |
| 39 | import_as_name: NAME [NAME NAME] |
| 40 | dotted_as_name: dotted_name [NAME NAME] |
| 41 | dotted_name: NAME ('.' NAME)* |
| 42 | */ |
| 43 | |
| 44 | /* future_parse() return values: |
| 45 | -1 indicates an error occurred, e.g. unknown feature name |
| 46 | 0 indicates no feature was found |
| 47 | 1 indicates a feature was found |
| 48 | */ |
| 49 | |
| 50 | static int |
| 51 | future_parse(PyFutureFeatures *ff, node *n) |
| 52 | { |
| 53 | int i, r, found; |
| 54 | loop: |
| 55 | |
| 56 | /* fprintf(stderr, "future_parse(%d, %d, %s)\n", |
| 57 | TYPE(n), NCH(n), (n == NULL) ? "NULL" : STR(n)); |
| 58 | */ |
| 59 | switch (TYPE(n)) { |
| 60 | |
| 61 | case file_input: |
| 62 | for (i = 0; i < NCH(n); i++) { |
| 63 | node *ch = CHILD(n, i); |
| 64 | if (TYPE(ch) == stmt) { |
| 65 | n = ch; |
| 66 | goto loop; |
| 67 | } |
| 68 | } |
| 69 | return 0; |
| 70 | |
| 71 | case simple_stmt: |
| 72 | if (NCH(n) == 1) { |
| 73 | REQ(CHILD(n, 0), small_stmt); |
| 74 | n = CHILD(n, 0); |
| 75 | goto loop; |
| 76 | } |
| 77 | found = 0; |
| 78 | for (i = 0; i < NCH(n); ++i) |
| 79 | if (TYPE(CHILD(n, i)) == small_stmt) { |
| 80 | r = future_parse(ff, CHILD(n, i)); |
| 81 | if (r < 1) { |
| 82 | ff->ff_last_lineno = n->n_lineno; |
| 83 | ff->ff_n_simple_stmt = i; |
| 84 | return r; |
| 85 | } else |
| 86 | found++; |
| 87 | } |
| 88 | if (found) |
| 89 | return 1; |
| 90 | else |
| 91 | return 0; |
| 92 | |
| 93 | case stmt: |
| 94 | if (TYPE(CHILD(n, 0)) == simple_stmt) { |
| 95 | n = CHILD(n, 0); |
| 96 | goto loop; |
| 97 | } else { |
| 98 | REQ(CHILD(n, 0), compound_stmt); |
| 99 | ff->ff_last_lineno = n->n_lineno; |
| 100 | return 0; |
| 101 | } |
| 102 | |
| 103 | case small_stmt: |
| 104 | n = CHILD(n, 0); |
| 105 | goto loop; |
| 106 | |
| 107 | case import_stmt: { |
| 108 | node *name; |
| 109 | |
| 110 | if (STR(CHILD(n, 0))[0] != 'f') { /* from */ |
| 111 | ff->ff_last_lineno = n->n_lineno; |
| 112 | return 0; |
| 113 | } |
| 114 | name = CHILD(n, 1); |
| 115 | if (strcmp(STR(CHILD(name, 0)), "__future__") != 0) |
| 116 | return 0; |
| 117 | if (future_check_features(ff, n) < 0) |
| 118 | return -1; |
| 119 | return 1; |
| 120 | } |
| 121 | |
| 122 | default: |
| 123 | ff->ff_last_lineno = n->n_lineno; |
| 124 | return 0; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | PyFutureFeatures * |
| 129 | PyNode_Future(node *n, char *filename) |
| 130 | { |
| 131 | PyFutureFeatures *ff; |
| 132 | |
| 133 | ff = (PyFutureFeatures *)PyMem_Malloc(sizeof(PyFutureFeatures)); |
| 134 | if (ff == NULL) |
| 135 | return NULL; |
| 136 | ff->ff_last_lineno = 0; |
| 137 | ff->ff_n_simple_stmt = -1; |
| 138 | ff->ff_nested_scopes = 0; |
| 139 | |
| 140 | if (future_parse(ff, n) < 0) { |
| 141 | PyMem_Free((void *)ff); |
| 142 | return NULL; |
| 143 | } |
| 144 | return ff; |
| 145 | } |
| 146 | |