start writing psql module, start writing exercise 1 with that module, small header file changes as needed for module programming

6 files changed, 118 insertions, 9 deletions

diff --git a/Makefile b/Makefile
index d574b4e..ad69623 100644
--- a/Makefile
+++ b/Makefile
@@ -5,8 +5,9 @@ CFLAGS  = -DYYDEBUG=1 -fPIC
 LIBS    = -lreadline -lfl -lm
 OBJS	= lisp.o lisp.tab.o lex.yy.o
 
-MODULE_SRC = $(wildcard modules/*.c)
-MODULE_SO = $(MODULE_SRC:.c=.so)
+MODULE_LIBS = -lpq
+MODULE_SRC  = $(wildcard modules/*.c)
+MODULE_SO   = $(MODULE_SRC:.c=.so)
 .SUFFIXES:
 
 main: main.c $(OBJS)
@@ -48,7 +49,7 @@ modules: $(MODULE_SO)
 
 modules/%.so: modules/%.c lisp.o
 	gcc -fPIC -c $< -o $*.o
-	gcc -fPIC -shared $*.o lisp.o -o $@
+	gcc -fPIC -shared $*.o lisp.o -o $@ $(MODULE_LIBS)
 	rm $*.o
 
 .PHONY: clean test run
diff --git a/lisp.c b/lisp.c
index 8b9f3ad..88ff472 100644
--- a/lisp.c
+++ b/lisp.c
@@ -26,14 +26,14 @@ value *make_double(double d) {
 value *make_symbol(const char *s) {
 	value *val = malloc(sizeof(value));
 	val->type = VT_SYMBOL;
-	val->as.sym = s;
+	val->as.sym = strdup(s);
 	return val;
 }
 
 value *make_string(const char *s) {
 	value *val = malloc(sizeof(value));
 	val->type = VT_STRING;
-	val->as.str = s;
+	val->as.str = strdup(s);
 	return val;
 }
 
@@ -518,7 +518,7 @@ value *procedure_load_module(env *e, value *args) {
 		env_define(e, exports[i].name, exports[i].v);
 	}
 
-	return make_nil();
+	return make_int(1);
 }
 
 int is_integer(double x) {
diff --git a/lisp.h b/lisp.h
index 7d435ff..ef4505a 100644
--- a/lisp.h
+++ b/lisp.h
@@ -4,8 +4,6 @@
 typedef struct value value;
 typedef struct env env;
 
-void print_value(value *val);
-void println_value(value *val);
 // environments, TODO: make this use hashtable
 // symbol->val
 typedef struct env {
@@ -21,7 +19,6 @@ value *env_lookup(env *e, const char *sym);
 
 extern env *global_env;
 
-value *eval(env *e, value *val);
 value *eval_pair(env *e, value *val);
 
 value *apply(value *lambda, value *args);
diff --git a/lisp/exercise_1.lisp b/lisp/exercise_1.lisp
new file mode 100644
index 0000000..2828ae4
--- /dev/null
+++ b/lisp/exercise_1.lisp
@@ -0,0 +1,21 @@
+(load_module "modules/psql_lisp.so")
+(define result (pg_execute "dbname=pagilla user=postgres" "SELECT      category.name AS category_name,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 1) AS mon,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 2) AS tue,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 3) AS wed,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 4) AS thu,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 5) AS fri,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 6) AS sat,
+            COUNT(*) FILTER (WHERE EXTRACT(ISODOW FROM rental.rental_date) = 7) AS sun,
+            COUNT(*) AS total
+FROM        rental
+INNER JOIN  inventory
+ON          rental.inventory_id = inventory.inventory_id
+INNER JOIN  film_category
+ON          inventory.film_id = film_category.film_id
+INNER JOIN  category
+ON          film_category.category_id = category.category_id
+WHERE       EXTRACT(MONTH FROM rental.rental_date) = 6 AND 
+            EXTRACT(YEAR FROM rental.rental_date) = 2005
+GROUP BY    category.name
+ORDER BY    category.name"))
diff --git a/lisp_api.h b/lisp_api.h
index bb4bf6f..66ad231 100644
--- a/lisp_api.h
+++ b/lisp_api.h
@@ -4,6 +4,11 @@
 typedef struct value value;
 typedef struct env env;
 
+value *eval(env *e, value *val);
+
+void print_value(value *val);
+void println_value(value *val);
+
 typedef enum {
 	VT_INT,
 	VT_DOUBLE,
diff --git a/modules/psql_lisp.c b/modules/psql_lisp.c
new file mode 100644
index 0000000..87ea748
--- /dev/null
+++ b/modules/psql_lisp.c
@@ -0,0 +1,85 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <libpq-fe.h>
+#include "../lisp_api.h"
+
+value *hello_fun(env *e, value *args) {
+	printf("Hello from dynamically loaded module!\n");
+	return make_nil();
+}
+
+value *pg_execute(env *e, value *args) {
+	value *fst_arg = eval(e, car(args));
+	value *snd_arg = eval(e, car(cdr(args)));
+
+	if (fst_arg->type != VT_STRING) {
+		printf("not a string:");
+		println_value(fst_arg);
+		return make_nil(); //TODO: make error
+	}
+	if (snd_arg->type != VT_STRING) {
+		printf("not a string:");
+		println_value(snd_arg);
+		return make_nil(); //TODO: make error
+	}
+
+	const char *conn_str = fst_arg->as.str;
+	const char *query_str = snd_arg->as.str;
+
+	PGconn *conn = PQconnectdb(conn_str);
+	if (PQstatus(conn) != CONNECTION_OK) {
+		fprintf(stderr, "Connection failed: %s", PQerrorMessage(conn));
+		PQfinish(conn);
+		return make_nil(); //TODO: make error
+	}
+
+	PGresult *res = PQexec(conn, query_str);
+	if (PQresultStatus(res) != PGRES_TUPLES_OK) {
+		fprintf(stderr, "Query failed: %s", PQerrorMessage(conn));
+		PQclear(res);
+		PQfinish(conn);
+		return make_nil(); //TODO: make error
+	}
+
+	int rows = PQntuples(res);
+	int cols = PQnfields(res);
+
+	value *table = make_nil();
+
+	for (int row = 0; row < rows; row++) {
+		value *row_val = make_nil();
+		for (int col = 0; col < cols; col++) {
+			switch (PQftype(res, col)) {
+				case 23:
+					row_val=cons(make_int(atoi(PQgetvalue(res, row, col))), row_val);
+				break;
+				case 1700:
+				case 20:
+					row_val=cons(make_int(atof(PQgetvalue(res, row, col))), row_val);
+				break;
+				default:
+					const char *str;
+					row_val=cons(make_string(PQgetvalue(res, row, col)), row_val);
+				break;
+			}
+		}
+		table = cons(reverse(row_val), table);
+	}
+	PQclear(res);
+	PQfinish(conn);
+
+	table = reverse(table);
+	return table;
+}
+
+module_export *module_init() {
+	static module_export exports[2];
+
+	exports[0].name = "pg_execute";
+	exports[0].v    = make_procedure(&pg_execute);
+
+	exports[1].name = NULL;
+	exports[1].v    = NULL;
+
+	return exports;
+}