diff --git a/c/mapping/mlr_dsl_cst.h b/c/mapping/mlr_dsl_cst.h
index 068c2d85f..0093c3ef7 100644
--- a/c/mapping/mlr_dsl_cst.h
+++ b/c/mapping/mlr_dsl_cst.h
@@ -71,17 +71,26 @@ typedef struct _cst_outputs_t {
 	cli_writer_opts_t* pwriter_opts;
 } cst_outputs_t;
 
+// ----------------------------------------------------------------
 typedef struct _cst_top_level_statement_block_t {
 	local_stack_t* pstack;
 	int max_var_depth;
 	sllv_t* pstatements;
 } cst_top_level_statement_block_t;
 
+cst_top_level_statement_block_t* cst_top_level_statement_block_alloc(int max_var_depth);
+void cst_top_level_statement_block_free(cst_top_level_statement_block_t* pblock);
+
+// ----------------------------------------------------------------
 typedef struct _cst_statement_block_t {
 	int frame_var_count;
 	sllv_t* pstatements;
 } cst_statement_block_t;
 
+cst_statement_block_t* cst_statement_block_alloc(int frame_var_count);
+void cst_statement_block_free(cst_statement_block_t* pblock);
+
+// ----------------------------------------------------------------
 // Generic handler for a statement.
 typedef void mlr_dsl_cst_node_handler_func_t(
 	struct _mlr_dsl_cst_statement_t* pnode,
diff --git a/c/mapping/mlr_dsl_cst_statements.c b/c/mapping/mlr_dsl_cst_statements.c
index cbf2e51df..f53b029d3 100644
--- a/c/mapping/mlr_dsl_cst_statements.c
+++ b/c/mapping/mlr_dsl_cst_statements.c
@@ -222,7 +222,51 @@ static cst_statement_handler_t handle_dump;
 static cst_statement_handler_t handle_dump_to_file;
 static cst_statement_handler_t handle_print;
 
+// ================================================================
+cst_top_level_statement_block_t* cst_top_level_statement_block_alloc(int max_var_depth) {
+	cst_top_level_statement_block_t* pblock = mlr_malloc_or_die(sizeof(cst_top_level_statement_block_t));
+
+	pblock->max_var_depth = max_var_depth;
+	pblock->pstack        = local_stack_alloc(max_var_depth);
+	pblock->pstatements   = sllv_alloc();
+
+	return pblock;
+}
+
 // ----------------------------------------------------------------
+void cst_top_level_statement_block_free(cst_top_level_statement_block_t* pblock) {
+	if (pblock == NULL)
+		return;
+	local_stack_free(pblock->pstack);
+	for (sllve_t* pe = pblock->pstatements->phead; pe != NULL; pe = pe->pnext) {
+		mlr_dsl_cst_statement_free(pe->pvvalue);
+	}
+	sllv_free(pblock->pstatements);
+	free(pblock);
+}
+
+// ----------------------------------------------------------------
+cst_statement_block_t* cst_statement_block_alloc(int frame_var_count) {
+	cst_statement_block_t* pblock = mlr_malloc_or_die(sizeof(cst_statement_block_t));
+
+	pblock->frame_var_count = frame_var_count;
+	pblock->pstatements     = sllv_alloc();
+
+	return pblock;
+}
+
+// ----------------------------------------------------------------
+void cst_statement_block_free(cst_statement_block_t* pblock) {
+	if (pblock == NULL)
+		return;
+	for (sllve_t* pe = pblock->pstatements->phead; pe != NULL; pe = pe->pnext) {
+		mlr_dsl_cst_statement_free(pe->pvvalue);
+	}
+	sllv_free(pblock->pstatements);
+	free(pblock);
+}
+
+// ================================================================
 // The parser accepts many things that are invalid, e.g.
 // * begin{end{}} -- begin/end not at top level
 // * begin{$x=1} -- references to stream records at begin/end