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Added the abilty for lambda expressions to be added into the AST. Have not added logic to properly evaulate lambda expressions yet. Currently defaults to a long with the value 0.

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Brandon Rozek 2018-09-24 14:21:32 -04:00
parent 3b6198669f
commit 82f7e21d3a
3 changed files with 19 additions and 4 deletions
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2
src/lexer.l
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@ -39,6 +39,8 @@ DIGIT [0-9]
"while" {return WHILE;}
"print" {return PRINT;}
"input" {return INPUT;}
"lambda" {return LAMBDA;}
":" {return COLON;}
"true" {yylval.value = make_node(VALUE, make_value(BOOLEAN, 1, 0), ""); return VALUE;}
"false" {yylval.value = make_node(VALUE, make_value(BOOLEAN, 0, 0), ""); return VALUE;}
{DIGIT} {yylval.value = make_node(VALUE, make_value(LONG, atoi(yytext), 0), ""); return VALUE;}

1
src/node.h
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@ -4,6 +4,7 @@
#define ID_SIZE 100
#define MAX_CHILDREN 3
#define STATEMENT 200
#define CALLFUNC 201
#define MAX_VARIABLES 200
enum TypeTag { DOUBLE, LONG, BOOLEAN };

20
src/parser.y
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@ -51,9 +51,11 @@ struct Node* result;
%token COMMENT
%token WHITESPACE
%token DONE
%token <value> LAMBDA
%token COLON
/* declare non-terminals */
%type <value> program statement assignment if-statement if-else-statement while print statements substatements expression subexpression term subterm factor atom identvalue ident
%type <value> program statement assignment if-statement if-else-statement while print statements substatements callfunc expression subexpression term subterm factor atom identvalue ident
/* give us more detailed errors */
%error-verbose
@ -135,9 +137,17 @@ atom: OPENPAREM expression ENDPAREM { $$ = $2; }
ident: IDENTIFIER { $$ = $1; }
identvalue: IDENTIFIER { $$ = $1; }
callfunc: ident OPENPAREM ident ENDPAREM { $$ = make_node(CALLFUNC, NULL, 0); attach_node($$, $1); attach_node($$, $3); }
identvalue: callfunc { $$ = $1; }
| ident { $$ = $1; }
| VALUE { $$ = $1; }
| INPUT { $$ = make_node(INPUT, NULL , ""); }
| LAMBDA ident COLON expression {
// Only supports one argument functions for now
$$ = make_node(LAMBDA, NULL, "");
attach_node($$, $2);
attach_node($$, $4); }
@ -244,6 +254,7 @@ void print_tree(struct Node* node, int tabs) {
case WHILE: printf("WHILE:\n"); break;
case PRINT: printf("PRINT:\n"); break;
case INPUT: printf("INPUT:\n"); break;
case LAMBDA: printf("LAMBDA:\n"); break;
case STATEMENT: printf("STATEMENT:\n"); break;
case VALUE:
if (node->value->type == BOOLEAN) {
@ -642,11 +653,11 @@ struct Value* eval_expression(struct Node* node, struct Environment* env) {
double temp;
struct Variable* var = NULL;
// Evaluate subexpressions if existent
// Evaluate subexpressions if existent and node is not a lambda expression
struct Value* val1 = NULL;
struct Value* val2 = NULL;
struct Value* val3 = NULL;
if (node->num_children > 0) {
if (node->num_children > 0 && node->type != LAMBDA) {
val1 = eval_expression(node->children[0], env);
if (node->num_children > 1) {
val2 = eval_expression(node->children[1], env);
@ -658,6 +669,7 @@ struct Value* eval_expression(struct Node* node, struct Environment* env) {
}
switch(node->type) {
case LAMBDA: printf("<LambdaExpression>\n"); return make_long(0); break;
case PLUS:
check_num_nodes(node, 2, "cannot add more than two expressions.");
return add(val1, val2);