Major overhaul refactor restructuring

1 files changed, 93 insertions, 0 deletions

diff --git a/grammar.c b/grammar.c
new file mode 100644
index 0000000..c04587b
--- /dev/null
+++ b/grammar.c
@@ -0,0 +1,93 @@
+/*
+ * grammar.c - Code for defining grammars (sets of rules)
+ */
+
+#include "grammar.h"
+#include "compiler.h"
+#include "utils.h"
+
+const char *BPEG_BUILTIN_GRAMMAR = (
+    "crlf=\\r\\n;\n"
+    "cr=\\r;\n" "r=\\r;\n"
+    "anglebraces=`< *(anglebraces / ~~`>) `>;\n"
+    "brackets=`[ *(brackets / ~~`]) `];\n"
+    "braces=`{ *(braces / ~~`}) `};\n"
+    "parens=`( *(parens / ~~`)) `);\n"
+    "id=(`a-z/`A-Z/`_) *(`a-z/`A-Z/`_/`0-9);\n"
+    "HEX=`0-9/`A-F;\n"
+    "Hex=`0-9/`a-f/`A-F;\n"
+    "hex=`0-9/`a-f;\n"
+    "number=+`0-9 ?(`. *`0-9) / `. +`0-9;\n"
+    "int=+`0-9;\n"
+    "digit=`0-9;\n"
+    "Abc=`a-z/`A-Z;\n"
+    "ABC=`A-Z;\n"
+    "abc=`a-z;\n"
+    "esc=\\e;\n" "e=\\e;\n"
+    "tab=\\t;\n" "t=\\t;\n"
+    "nl=\\n;\n" "lf=\\n;\n" "n=\\n;\n"
+    "c-block-comment='/*' &&'*/';\n"
+    "c-line-comment='//' &$;\n"
+    "c-comment=c-line-comment / c-block-comment;\n"
+    "hash-comment=`# &$;\n"
+    "comment=!(/);\n" // No default definition, can be overridden
+    "WS=` /\\t/\\n/\\r/comment;\n"
+    "ws=` /\\t;\n"
+    "$$=!$.;\n"
+    "$=!.;\n"
+    "^^=!<$.;\n"
+    "^=!<.;\n"
+    "__=*(` /\\t/\\n/\\r/comment);\n"
+    "_=*(` /\\t);\n"
+    );
+
+grammar_t *new_grammar(void)
+{
+    grammar_t *g = calloc(sizeof(grammar_t), 1);
+    g->definitions = calloc(sizeof(def_t), (g->capacity = 128));
+    load_grammar(g, BPEG_BUILTIN_GRAMMAR);
+    return g;
+}
+
+void add_def(grammar_t *g, const char *src, const char *name, vm_op_t *op)
+{
+    if (g->size >= g->capacity) {
+        g->definitions = realloc(g->definitions, (g->capacity += 32));
+    }
+    int i = g->size;
+    g->definitions[i].source = src;
+    g->definitions[i].name = name;
+    g->definitions[i].op = op;
+    ++g->size;
+}
+
+void load_grammar(grammar_t *g, const char *src)
+{
+    vm_op_t *mainpat = NULL;
+    do {
+        src = after_spaces(src);
+        if (!*src) break;
+        const char *name = src;
+        const char *name_end = after_name(name);
+        check(name_end > name, "Invalid name for definition");
+        name = strndup(name, (size_t)(name_end-name));
+        src = after_spaces(name_end);
+        check(matchchar(&src, '='), "Expected '=' in definition");
+        vm_op_t *op = bpeg_pattern(src);
+        check(op, "Couldn't load definition");
+        add_def(g, src, name, op);
+        if (mainpat == NULL) {
+            mainpat = op;
+            g->pattern = op;
+        }
+        src = op->end;
+    } while (*src && matchchar(&src, ';')); 
+}
+
+/*
+ * Print a BPEG grammar in human-readable form.
+ */
+void print_grammar(grammar_t *g)
+{
+    if (g->pattern) print_pattern(g->pattern);
+}