2 files changed, 100 insertions, 0 deletions
diff --git a/src/runtime/c/pgf/graphviz.c b/src/runtime/c/pgf/graphviz.c
new file mode 100644
index 000000000..cf2346fee
--- /dev/null
+++ b/src/runtime/c/pgf/graphviz.c
@@ -0,0 +1,93 @@
+#include "data.h"
+#include "graphviz.h"
+
+static int
+pgf_graphviz_abstract_tree_(PgfExpr expr, int *pid,
+                            GuWriter* wtr, GuExn* err)
+{
+	int id = -1;
+
+	GuVariantInfo ei = gu_variant_open(expr);
+	switch (ei.tag) {
+	case PGF_EXPR_ABS:
+		gu_impossible();
+		break;
+	case PGF_EXPR_APP: {
+		PgfExprApp* app = ei.data;
+		id = pgf_graphviz_abstract_tree_(app->fun, pid, wtr, err);
+		int arg_id = pgf_graphviz_abstract_tree_(app->arg, pid, wtr, err);
+		gu_printf(wtr, err, "n%d -- n%d [style = \"solid\"]\n", id, arg_id);
+		break;
+	}
+	case PGF_EXPR_LIT: {
+		PgfExprLit* lit = ei.data;
+		id = (*pid)++;
+		gu_printf(wtr, err, "n%d[label = \"", id);
+		
+		GuVariantInfo ei = gu_variant_open(lit->lit);
+		switch (ei.tag) {
+		case PGF_LITERAL_STR: {
+			PgfLiteralStr* lit = ei.data;
+			gu_puts("\\\"", wtr, err);
+			gu_string_write(lit->val, wtr, err);
+			gu_puts("\\\"", wtr, err);
+			break;
+		}
+		case PGF_LITERAL_INT: {
+			PgfLiteralInt* lit = ei.data;
+			gu_printf(wtr, err, "%d", lit->val);
+			break;
+		}
+		case PGF_LITERAL_FLT: {
+			PgfLiteralFlt* lit = ei.data;
+			gu_printf(wtr, err, "%lf", lit->val);
+			break;
+		}
+		default:
+			gu_impossible();
+		}
+
+		gu_puts("\", style = \"solid\", shape = \"plaintext\"]\n", wtr, err);
+		break;
+	}
+	case PGF_EXPR_META:
+		id = (*pid)++;
+		gu_printf(wtr, err, "n%d[label = \"?\", style = \"solid\", shape = \"plaintext\"]\n", id);
+		break;
+	case PGF_EXPR_FUN: {
+		PgfExprFun* fun = ei.data;
+		id = (*pid)++;
+		gu_printf(wtr, err, "n%d[label = \"", id);
+		gu_string_write(fun->fun, wtr, err);
+		gu_puts("\", style = \"solid\", shape = \"plaintext\"]\n", wtr, err);
+		break;
+	}
+	case PGF_EXPR_VAR:
+		gu_impossible();
+		break;
+	case PGF_EXPR_TYPED: {
+		PgfExprTyped* typed = ei.data;
+		id = pgf_graphviz_abstract_tree_(typed->expr, pid, wtr, err);
+		break;
+	}
+	case PGF_EXPR_IMPL_ARG: {
+		PgfExprImplArg* implarg = ei.data;
+		id = pgf_graphviz_abstract_tree_(implarg->expr, pid, wtr, err);
+		break;
+	}
+	default:
+		gu_impossible();
+	}
+
+	return id;
+}
+
+void
+pgf_graphviz_abstract_tree(PgfExpr expr, GuWriter* wtr, GuExn* err)
+{
+	int id = 0;
+
+	gu_puts("graph {\n", wtr, err);
+	pgf_graphviz_abstract_tree_(expr, &id, wtr, err);
+	gu_puts("}", wtr, err);
+}
diff --git a/src/runtime/c/pgf/graphviz.h b/src/runtime/c/pgf/graphviz.h
new file mode 100644
index 000000000..749c6ef5f
--- /dev/null
+++ b/src/runtime/c/pgf/graphviz.h
@@ -0,0 +1,7 @@
+#ifndef PGF_GRAPHVIZ_H_
+#define PGF_GRAPHVIZ_H_
+
+void
+pgf_graphviz_abstract_tree(PgfExpr expr, GuWriter* wtr, GuExn* err);
+
+#endif