From 77263f95bbbc9d8c91ab77726f02f445a1e3f367 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Mon, 8 Aug 2016 21:18:52 +0200
Subject: Basic if statements

---
 code.txt |  9 ++++++++-
 parser.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 66 insertions(+), 9 deletions(-)

diff --git a/code.txt b/code.txt
index 07e132d..783d1b5 100644
--- a/code.txt
+++ b/code.txt
@@ -8,6 +8,13 @@ x = 1 + 1 + 1 + 1;
 y = 1 > (1 > 1) == 1;
 kaas(1,2,"goeiemorgen\x99",sqrt(3**2+4**2));
 1 + 1 + 1;
-1 - 1 - 1;
+if (2 > 1) 1 - 1 - 1;
 1 / 1 / 1;
 1 ** 1 ** 1;
+
+if kaas
+	doe(dingen)
+else if andere(kaas)
+	doe(andere,dingen)
+else
+	print("rip");
diff --git a/parser.c b/parser.c
index 857b11d..7ed64a6 100644
--- a/parser.c
+++ b/parser.c
@@ -11,7 +11,7 @@
 #include "parser.h"
 
 
-#undef DEBUG
+#define DEBUG
 
 #ifdef DEBUG
 #define DBG(...) __VA_ARGS__
@@ -51,7 +51,7 @@ typedef enum Tokentype{
 
 typedef struct Token{
 	Tokentype type;
-	const char *str; //Part of another string; not null-terminated, and do not free
+	const char *str; //Pointer into source string, or NULL if TT_EOF
 	int len;
 } Token;
 
@@ -253,7 +253,39 @@ static AST* parseterm(const char *source,int *reslen){
 		}
 
 		case TT_WORD:{
-			if(tok.len==2&&memcmp(tok.str,"if",2)==0)assert(NOT_IMPLEMENTED);
+			if(tok.len==2&&memcmp(tok.str,"if",2)==0){
+				int len;
+				AST *cond=parseexpr(source,&len,0,INT_MAX);
+				if(!cond)return NULL;
+				source+=len;
+				AST *thenbody=parseexpr(source,&len,0,INT_MAX);
+				if(!thenbody){
+					ast_free(cond);
+					return NULL;
+				}
+				source+=len;
+				AST *elsebody=NULL;
+				const char *src=source;
+				Token elsetok=nexttoken(&src,false);
+				if(elsetok.type==TT_WORD&&elsetok.len==4&&memcmp(elsetok.str,"else",4)==0){
+					DBG(printtoken(stderr,elsetok,"if else  "));
+					source=src;
+					elsebody=parseexpr(source,&len,0,INT_MAX);
+					if(!elsebody){
+						ast_free(cond);
+						ast_free(thenbody);
+						return NULL;
+					}
+					source+=len;
+				}
+				node=malloc(sizeof(AST));
+				if(!node)outofmem();
+				node->type=AST_IF;
+				node->i.cond=cond;
+				node->i.thenb=thenbody;
+				node->i.elseb=elsebody;
+				break;
+			}
 			if(tok.len==5&&memcmp(tok.str,"while",2)==0)assert(NOT_IMPLEMENTED);
 			const char *tempsource=source;
 			Token next=nexttoken(&source,false);
@@ -381,8 +413,11 @@ static AST* parseexpr_(const char *source,int *reslen,int minprec,int maxprec){
 			break;
 		}
 		if(tok.type!=TT_OP){
-			ast_free(tree);
-			return NULL;
+			/*ast_free(tree);
+			return NULL;*/
+			DBGF("  (token undo)\n");
+			source=beforeop;
+			break;
 		}
 		int prec=precedence_len(tok.str,tok.len);
 		if(prec<minprec){
@@ -538,7 +573,7 @@ static void ast_debug_(FILE *stream,const AST *ast,int indent){
 			for(int i=0;i<ast->b.len;i++){
 				INDENT
 				ast_debug_(stream,ast->b.exprs[i],indent);
-				fputc('\n',stream);
+				fprintf(stream,";\n");
 			}
 			indent--;
 			INDENT
@@ -580,14 +615,29 @@ static void ast_debug_(FILE *stream,const AST *ast,int indent){
 		case AST_CALL:
 			fprintf(stream,"%s(",ast->c.func);
 			for(int i=0;i<ast->c.nargs;i++){
-				if(i!=0)fputc(',',stream);
+				if(i!=0)fprintf(stream,", ");
 				ast_debug_(stream,ast->c.args[i],indent);
 			}
 			fputc(')',stream);
 			break;
 
 		case AST_IF:
-			assert(NOT_IMPLEMENTED);
+			fprintf(stream,"if (");
+			ast_debug_(stream,ast->i.cond,indent);
+			fprintf(stream,")\n");
+			indent++;
+			INDENT
+			ast_debug_(stream,ast->i.thenb,indent);
+			indent--;
+			if(ast->i.elseb){
+				fputc('\n',stream);
+				INDENT
+				fprintf(stream,"else\n");
+				indent++;
+				INDENT
+				ast_debug_(stream,ast->i.elseb,indent);
+				indent--;
+			}
 			break;
 
 		case AST_WHILE:
-- 
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