wip: working on analyzer

- Feat: add `nest_ctx` and `fin_ctx` fns for working with context and
environment
- Feat: add block analyzer
- Feat: add conditional statement analyzer

src/compiler/analyzer/an_block.c

@@ -0,0 +1,44 @@
+#include <common/fzl_types.h>
+#include <compiler/fzl_analyzer.h>
+#include <compiler/fzl_parser.h>
+#include <stddef.h>
+#include <stdio.h>
+
+char block_problem[256];
+
+// Analyze block
+fzl_an_res_t analyze_block(fzl_analyzer_t *analyzer, fzl_node_t *block_node)
+{
+  if (!analyzer)
+    return (fzl_an_res_t){.error = true};
+
+  if (!block_node || block_node->type != FZL_NODETYPE_BLOCK)
+  {
+    snprintf(block_problem, sizeof(block_problem), "node is not typeof BLOCK");
+    an_push_error(analyzer, NULL, block_problem);
+    return (fzl_an_res_t){.error = true};
+  }
+
+  an_nest_ctx(analyzer, FZL_AN_CTX_TYPE_UNNECESSARY);
+
+  bool has_return = false;
+  bool error      = false;
+  for (size_t i = 0; i < block_node->list.entry_count; i++)
+  {
+    if (has_return)
+      an_push_warning(analyzer, block_node->list.entries[i]->token,
+                      "this node will never execute");
+
+    fzl_an_res_t entry_res =
+        analyze_common(analyzer, block_node->list.entries[i]);
+    if (entry_res.error)
+      error = true;
+
+    if (block_node->list.entries[i]->type == FZL_NODETYPE_RETURN)
+      has_return = true;
+  }
+
+  an_fin_ctx(analyzer);
+
+  return (fzl_an_res_t){.error = error, .type = FZL_TYPE_NULL};
+}