started to work in the ast

src/model.c

@@ -1,36 +1,58 @@
 #include "model.h"
 
-struct expression
+#include <stdlib.h>
+
+struct expression *
+alloc_expr ()
+{
+	return (struct expression *)calloc (1, sizeof (struct expression));
+}
+
+struct expression *
 expression_create_integer (int value)
 {
-	return (struct expression){ .type = EXPR_INT, .integer = value };
+	struct expression *expr = alloc_expr ();
+	expr->type = EXPR_INT;
+	expr->integer = value;
+	return expr;
 }
 
-struct expression
-expression_create_floating (int value)
+struct expression *
+expression_create_floating (float value)
 {
-	return (struct expression){ .type = EXPR_FLOAT, .floating = value };
+	struct expression *expr = alloc_expr ();
+	expr->type = EXPR_FLOAT;
+	expr->floating = value;
+	return expr;
 }
 
-struct expression
+struct expression *
 expression_create_binop (struct token *op, struct expression *left,
 												 struct expression *right)
 {
-	return (struct expression){ .type = EXPR_BINOP,
-															.binop
-															= { .op = op, .left = left, .right = right } };
+	struct expression *expr = alloc_expr ();
+	expr->type = EXPR_BINOP;
+	expr->binop.op = op;
+	expr->binop.left = left;
+	expr->binop.right = right;
+	return expr;
 }
 
-struct expression
+struct expression *
 expression_create_unop (struct token *op, struct expression *operand)
 {
-	return (struct expression){ .type = EXPR_UNOP,
-															.unop = { .op = op, .operand = operand } };
+	struct expression *expr = alloc_expr ();
+	expr->type = EXPR_UNOP;
+	expr->unop.op = op;
+	expr->unop.operand = operand;
+	return expr;
 }
 
-struct expression
+struct expression *
 expression_create_grouping (struct expression *value)
 {
-	return (struct expression){ .type = EXPR_GROUP,
-															.grouping = { .value = value } };
+	struct expression *expr = alloc_expr ();
+	expr->type = EXPR_GROUP;
+	expr->grouping.value = value;
+	return expr;
 }

src/model.h

@@ -3,16 +3,15 @@
 
 #include "token.h"
 
-/********************************
- * Expression
- ********************************/
 enum expression_type
 {
 	EXPR_INT,
 	EXPR_FLOAT,
 	EXPR_BINOP,
 	EXPR_UNOP,
-	EXPR_GROUP
+	EXPR_GROUP,
+
+	/* TODO: Statements */
 };
 
 struct expression
@@ -48,31 +47,16 @@ struct expression
 			struct expression *value;
 		} grouping;
 	};
+
+	/* TODO: Statements */
 };
-struct expression expression_create_integer (int value);
-struct expression expression_create_floating (int value);
-struct expression expression_create_binop (struct token *op,
+struct expression *expression_create_integer (int value);
+struct expression *expression_create_floating (float value);
+struct expression *expression_create_binop (struct token *op,
 																						struct expression *left,
 																						struct expression *right);
-struct expression expression_create_unop (struct token *op,
+struct expression *expression_create_unop (struct token *op,
 																					 struct expression *operand);
-struct expression expression_create_grouping (struct expression *value);
-
-/********************************
- * Statements
- ********************************/
-struct stmt
-{
-	union
-	{
-		struct
-		{
-		} while_stmt;
-
-		struct
-		{
-		} assignment;
-	};
-};
+struct expression *expression_create_grouping (struct expression *value);
 
 #endif

src/parser.c

@@ -1,11 +1,168 @@
 #include "parser.h"
 
 #include <stdio.h>
+#include <stdlib.h>
+
+#include "model.h"
+
+/* prototypes */
+struct expression *primary (struct parser *p);
+struct expression *unary (struct parser *p);
+struct expression *factor (struct parser *p);
+struct expression *term (struct parser *p);
+struct expression *expression (struct parser *p);
+
+/* util functions */
+/* static struct token * */
+/* advance (struct parser *p) */
+/* { */
+/*	if (!p) */
+/*		return NULL; */
+
+/*	if (p->curr >= vector_len (p->tokens)) */
+/*		return NULL; */
+
+/*	struct token *tok = (struct token *)vector_at (p->curr, p->tokens); */
+/*	p->curr++; */
+/*	return tok; */
+/* } */
+
+/* static struct token * */
+/* peek (struct parser *p) */
+/* { */
+/*	if (!p) */
+/*		return NULL; */
+
+/*	return (struct token *)vector_at (p->curr, p->tokens); */
+/* } */
+
+/* static _Bool */
+/* expect (enum token_type type, struct parser *p) */
+/* { */
+/*	if (!p) */
+/*		return 0; */
+
+/*	struct token *tok = (struct token *)vector_at (p->curr, p->tokens); */
+/*	return tok->type == type; */
+/* } */
+
+static struct token *
+prev_tok (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	if (p->curr <= 0)
+		return NULL;
+
+	return (struct token *)vector_at (p->curr - 1, p->tokens);
+}
+
+static struct token *
+match (enum token_type type, struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	struct token *tok = (struct token *)vector_at (p->curr, p->tokens);
+	if (!tok || tok->type != type)
+		return NULL;
+
+	p->curr++;
+	return tok;
+}
+
+/* recursively descending functions */
+struct expression *
+primary (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	struct token *tok = NULL;
+	if ((tok = match (TOK_INTEGER, p)))
+		return expression_create_integer (atoi (buffer_get (&tok->lexeme)));
+	if ((tok = match (TOK_FLOAT, p)))
+		return expression_create_floating (atof (buffer_get (&tok->lexeme)));
+	if ((tok = match (TOK_LPAREN, p)))
+		{
+			struct expression *expr = expression (p);
+			if (!(tok = match (TOK_RPAREN, p)))
+				{
+					fprintf (stderr, "Error: `)' expected at line %d.\n", tok->line);
+					exit (1);
+				}
+			return expression_create_grouping (expr);
+		}
+	return NULL; /* unmatched */
+}
+
+struct expression *
+unary (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	if (match (TOK_NOT, p) || match (TOK_MINUS, p) || match (TOK_PLUS, p))
+		{
+			struct token *op = prev_tok (p);
+			struct expression *right = unary (p);
+			return expression_create_unop (op, right);
+		}
+
+	return primary (p);
+}
+
+struct expression *
+factor (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	return unary (p);
+}
+
+struct expression *
+term (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	struct expression *expr = factor (p);
+	while (match (TOK_STAR, p) || match (TOK_SLASH, p))
+		{
+			struct token *op = prev_tok (p);
+			struct expression *right = factor (p);
+			expr = expression_create_binop (op, expr, right);
+		}
+
+	return expr;
+}
+
+struct expression *
+expression (struct parser *p)
+{
+	if (!p)
+		return NULL;
+
+	struct expression *expr = term (p);
+	while (match (TOK_PLUS, p) || match (TOK_MINUS, p))
+		{
+			struct token *op = prev_tok (p);
+			struct expression *right = term (p);
+			expr = expression_create_binop (op, expr, right);
+		}
+
+	return expr;
+}
 
 struct parser
 parser_create (struct vector *tokens)
 {
-	return (struct parser){ .tokens = tokens, .curr = 0 };
+	struct parser parser = { 0 };
+	parser.tokens = tokens;
+	parser.ast = vector_create ();
+	return parser;
 }
 
 void
@@ -13,10 +170,52 @@ parser_parse (struct parser *p)
 {
 	if (!p)
 		return;
+
+	vector_push_back (expression (p), &p->ast);
+}
+
+void
+expr_print (struct expression *expr)
+{
+	switch (expr->type)
+		{
+		case EXPR_INT:
+			printf ("Integer[%d]", expr->integer);
+			break;
+		case EXPR_FLOAT:
+			printf ("Float[%f]", expr->floating);
+			break;
+		case EXPR_BINOP:
+			printf ("BinOp('%s', ", buffer_get (&expr->binop.op->lexeme));
+			expr_print (expr->binop.left);
+			printf (", ");
+			expr_print (expr->binop.right);
+			printf (")");
+			break;
+		case EXPR_UNOP:
+			printf ("UnOp('%s', ", buffer_get (&expr->unop.op->lexeme));
+			expr_print (expr->unop.operand);
+			printf (")");
+			break;
+		case EXPR_GROUP:
+			printf ("Grouping(");
+			expr_print (expr->grouping.value);
+			printf (")");
+			break;
+		default:
+			fprintf (stderr, "Unknown expression type: %d\n", expr->type);
+			break;
+		}
 }
 
 void
 parser_print (struct parser *p)
 {
-	puts ("Parser:");
+	puts ("Parsed Ast:");
+	for (unsigned int i = 0; i < vector_len (&p->ast); i++)
+		{
+			struct expression *expr = (struct expression *)vector_at (i, &p->ast);
+			expr_print (expr);
+			printf ("\n");
+		}
 }

src/parser.h

@@ -6,6 +6,7 @@
 struct parser
 {
 	struct vector *tokens;
+	struct vector ast;
 	unsigned int curr;
 };
 

src/utils/vector.c

@@ -50,7 +50,7 @@ vector_at (size_t i, struct vector *v)
 	if (!v)
 		return NULL;
 
-	if (i >= v->length)
+	if (i > v->length)
 		{
 			fprintf (stderr,
 							 "vector_at: cannot access index '%lu' in an array of '%lu' "
@@ -61,6 +61,15 @@ vector_at (size_t i, struct vector *v)
 	return v->elements[i];
 }
 
+size_t
+vector_len (struct vector *v)
+{
+	if (!v)
+		return 0;
+
+	return v->length;
+}
+
 void
 vector_free (struct vector *v)
 {

src/utils/vector.h

@@ -15,6 +15,7 @@ struct vector
 struct vector vector_create ();
 _Bool vector_push_back (void *elm, struct vector *v);
 void *vector_at (size_t i, struct vector *v);
+size_t vector_len (struct vector *v);
 void vector_free (struct vector *v);
 
 #endif

tests/expr.pinky

@@ -1,4 +1,4 @@
 --------------------------------
 -- Evaluate a simple expression
 --------------------------------
-2 + 42 * 2 + (47 * -21)
+2 / 42.22 * 2 + (47 * -21)