It's alive.

2 files changed, 185 insertions, 0 deletions

diff --git a/input b/input
new file mode 100644
index 0000000..9c1f87e
--- /dev/null
+++ b/input
@@ -0,0 +1,3 @@
+Hello, {username}!
+@articles{{title} by {author}
+}
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..3fe5475
--- /dev/null
+++ b/main.c
@@ -0,0 +1,182 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+
+struct reus_list {
+    const char       *name;
+    const char       *data;
+    struct reus_list *list;
+    struct reus_list *next;
+};
+
+struct reus {
+    struct reus_list *variables;
+    char             *name;
+    char             *body;
+    int               opened;
+};
+
+typedef void *(*reus_state)(struct reus *r, char c);
+
+
+void reus_string_add(char **str, char c)
+{
+    int *header;
+    if (!*str) {
+        header    = malloc(9);
+        *str      = (char *) header + 8;
+        header[0] = 1;
+        header[1] = 0;
+        (*str)[0] = 0;
+    } else header = (int *)(*str - 8);
+    if (header[0] == ++header[1]) {
+        header = realloc(header, 8 + (header[0] <<= 1));
+        *str   = (char *) header + 8;
+    }
+    (*str)[header[1] - 1] = c;
+    (*str)[header[1]]     = 0;
+}
+
+
+struct reus_list *reus_list_new(const char       *name,
+                                const char       *data,
+                                struct reus_list *list,
+                                struct reus_list *next)
+{
+    struct reus_list *res = malloc(sizeof(*res));
+    res->name             = name;
+    res->data             = data;
+    res->list             = list;
+    res->next             = next;
+    return res;
+}
+
+struct reus_list *reus_list_union(struct reus_list *a, struct reus_list *b)
+{
+    if (!a) return b ? reus_list_union(b, 0) : 0;
+    return reus_list_new(a->name, a->data,
+                         reus_list_union(a->list, 0),
+                         reus_list_union(a->next, b));
+}
+
+struct reus_list *reus_list_get(struct reus_list *l, char *name)
+{
+    if (!l) return 0;
+    if (!strcmp(l->name, name)) return l;
+    return reus_list_get(l->next, name);
+}
+
+void reus_list_free(struct reus_list *l)
+{
+    if (l->list) reus_list_free(l->list);
+    if (l->next) reus_list_free(l->next);
+    free(l);
+}
+
+
+void reus_init(struct reus *r)
+{
+    r->variables = 0;
+    r->name      = 0;
+    r->body      = 0;
+    r->opened    = 0;
+}
+
+void reus_free(struct reus *r)
+{
+    if (r->variables) reus_list_free(r->variables);
+    if (r->name)      free(r->name - 8);
+    if (r->body)      free(r->body - 8);
+}
+
+
+void *reus_state_at(struct reus *r, char c);
+void *reus_state_subs(struct reus *r, char c);
+void *reus_state_text(struct reus *r, char c)
+{
+    if (c == '@') return reus_state_at;
+    if (c == '{') return reus_state_subs;
+    putchar(c);
+    return reus_state_text;
+}
+
+void *reus_state_subs(struct reus *r, char c)
+{
+    if (c == '}') {
+        struct reus_list *var = reus_list_get(r->variables, r->name);
+        if (var && var->data) {
+            printf("%s", var->data);
+        }
+        free(r->name - 8);
+        r->name = 0;
+        return reus_state_text;
+    }
+    reus_string_add(&r->name, c);
+    return reus_state_subs;
+}
+
+void reus_at(struct reus *r)
+{
+    struct reus_list *var = reus_list_get(r->variables, r->name);
+    for (var = var->list; var; var = var->next) {
+        char *c;
+        struct reus sr;
+        reus_state  s = reus_state_text;
+        reus_init(&sr);
+        sr.variables = reus_list_union(var->list, r->variables);
+        for (c = r->body; *c; ++c) {
+            s = s(&sr, *c);
+        }
+        reus_free(&sr);
+    }
+}
+void *reus_state_body(struct reus *r, char c);
+void *reus_state_at(struct reus *r, char c)
+{
+    if (c == '{') return reus_state_body;
+    reus_string_add(&r->name, c);
+    return reus_state_at;
+}
+
+void *reus_state_body(struct reus *r, char c)
+{
+    if (c == '{') ++r->opened;
+    if (c == '}' && !r->opened--) {
+        reus_at(r);
+        r->opened = 0;
+        free(r->name - 8);
+        r->name = 0;
+        free(r->body - 8);
+        r->body = 0;
+        return reus_state_text;
+    }
+    reus_string_add(&r->body, c);
+    return reus_state_body;
+}
+
+
+int main()
+{
+    int         c;
+    struct reus r;
+    reus_state  s = reus_state_text;
+    reus_init(&r);
+    r.variables =
+    reus_list_new("username", "aversey", 0,
+    reus_list_new("articles", 0,
+        reus_list_new(0, 0,
+            reus_list_new("title", "Smooth Sort", 0,
+            reus_list_new("author", "Edsger Dijkstra", 0, 0)),
+        reus_list_new(0, 0,
+            reus_list_new("title", "Your Own Site", 0,
+            reus_list_new("author", "Aleksey Veresov", 0, 0)),
+        reus_list_new(0, 0,
+            reus_list_new("title", "Bullshit", 0,
+            reus_list_new("author", "Ongo Gablogian", 0, 0)), 0))), 0));
+    while ((c = getchar()) != EOF) {
+        s = s(&r, c);
+    }
+    reus_free(&r);
+    return 0;
+}