From a4c9a32c3f8a8fc15743356865a206d9e54a7767 Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike@mdlowis.com>
Date: Sun, 20 May 2018 14:48:54 -0400
Subject: [PATCH] stripped down grammar. ignoring broken specs for now

---
 source/lexer.l  | 12 +++---------
 source/main.c   | 11 ++++++++---
 source/parser.c | 31 +++++++++++--------------------
 source/sclpl.h  | 10 +++++-----
 4 files changed, 27 insertions(+), 37 deletions(-)

diff --git a/source/lexer.l b/source/lexer.l
index d590817..c69e6bf 100644
--- a/source/lexer.l
+++ b/source/lexer.l
@@ -124,16 +124,10 @@ false {
 
 %%
 
-Tok* gettoken(Parser* ctx)
-{
-    Tok* tok = NULL;
-    int type = yylex();
-    if (type != T_END_FILE) {
-        tok = emalloc(sizeof(Tok));
-        tok->type = type;
+void gettoken(Parser* ctx, Tok* tok) {
+    tok->type = yylex();
+    if (tok->type != T_END_FILE)
         memcpy(&(tok->value), &Value, sizeof(Value));
-    }
-    return tok;
 }
 
 void fetchline(Parser* ctx)
diff --git a/source/main.c b/source/main.c
index 0a22d40..534ebd2 100644
--- a/source/main.c
+++ b/source/main.c
@@ -6,10 +6,15 @@ char* Artifact = "bin";
 /* Driver Modes
  *****************************************************************************/
 static int emit_tokens(void) {
-    Tok* token = NULL;
+    Tok token = { 0 };
     Parser* ctx = parser_new(NULL, stdin);
-    while(NULL != (token = gettoken(ctx)))
-        pprint_token(stdout, token, true);
+    while (1) {
+        gettoken(ctx, &token);
+        if (token.type == T_END_FILE)
+            break;
+        else
+            pprint_token(stdout, &token, true);
+    }
     return 0;
 }
 
diff --git a/source/parser.c b/source/parser.c
index 5b036eb..bb86726 100644
--- a/source/parser.c
+++ b/source/parser.c
@@ -39,12 +39,10 @@ AST* toplevel(Parser* p)
 {
     AST* ret = NULL;
     if (!match(p, T_END_FILE)) {
-        if (accept(p, T_REQUIRE))
-            ret = require(p);
-        else if (accept(p, T_DEF))
+        if (accept(p, T_DEF))
             ret = definition(p);
         else
-            error(p, "expressions are not allowed at the toplevel");
+            error(p, "only definitions are allowed at the toplevel");
     }
     return ret;
 }
@@ -208,27 +206,22 @@ static void type_annotation(Parser* p)
 Parser* parser_new(char* prompt, FILE* input)
 {
     Parser* parser  = emalloc(sizeof(Parser));
-    parser->line    = NULL;
-    parser->index   = 0;
-    parser->lineno  = 0;
+    memset(parser, 0, sizeof(Parser));
     parser->input   = input;
     parser->prompt  = prompt;
-    parser->tok     = NULL;
     return parser;
 }
 
 static void fetch(Parser* parser)
 {
-    parser->tok = gettoken(parser);
-    if (NULL == parser->tok)
-        parser->tok = &tok_eof;
+    gettoken(parser, &(parser->tok));
 }
 
 static Tok* peek(Parser* parser)
 {
-    if (NULL == parser->tok)
+    if (T_NONE == parser->tok.type)
         fetch(parser);
-    return parser->tok;
+    return &(parser->tok);
 }
 
 static bool parser_eof(Parser* parser)
@@ -238,8 +231,8 @@ static bool parser_eof(Parser* parser)
 
 static void parser_resume(Parser* parser)
 {
-    if ((NULL != parser->tok) && (&tok_eof != parser->tok))
-        parser->tok = NULL;
+    if ((T_NONE != parser->tok.type) && (T_END_FILE != parser->tok.type))
+        parser->tok.type = T_NONE;
     /* We ignore the rest of the current line and attempt to start parsing
      * again on the next line */
     fetchline(parser);
@@ -260,11 +253,9 @@ static bool match(Parser* parser, TokType type)
 static Tok* accept(Parser* parser, TokType type)
 {
     Tok* tok = peek(parser);
-    if (tok->type == type) {
-        parser->tok = NULL;
-        return tok;
-    }
-    return NULL;
+    if (tok->type == type)
+        parser->tok.type = T_NONE;
+    return tok;
 }
 
 static Tok* expect(Parser* parser, TokType type)
diff --git a/source/sclpl.h b/source/sclpl.h
index 7edd081..6c44a90 100644
--- a/source/sclpl.h
+++ b/source/sclpl.h
@@ -40,9 +40,9 @@ void vec_set(vec_t* vec, size_t index, void* data);
 /* Token Types
  *****************************************************************************/
 typedef enum {
-    T_ID, T_CHAR, T_INT, T_FLOAT, T_BOOL, T_STRING, T_LBRACE, T_RBRACE, T_LBRACK,
-    T_RBRACK, T_LPAR, T_RPAR, T_COMMA, T_SQUOTE, T_DQUOTE, T_END, T_COLON, T_AMP,
-    T_REQUIRE, T_DEF, T_IF, T_FN, T_THEN, T_ELSE, T_END_FILE
+    T_NONE, T_ID, T_CHAR, T_INT, T_FLOAT, T_BOOL, T_STRING, T_LBRACE, T_RBRACE,
+    T_LBRACK, T_RBRACK, T_LPAR, T_RPAR, T_COMMA, T_SQUOTE, T_DQUOTE, T_END,
+    T_COLON, T_AMP, T_REQUIRE, T_DEF, T_IF, T_FN, T_THEN, T_ELSE, T_END_FILE
 } TokType;
 
 typedef struct {
@@ -209,11 +209,11 @@ typedef struct {
     size_t lineno;
     FILE* input;
     char* prompt;
-    Tok* tok;
+    Tok tok;
 } Parser;
 
 // Lexer routines
-Tok* gettoken(Parser* ctx);
+void gettoken(Parser* ctx, Tok* tok);
 void fetchline(Parser* ctx);
 
 // Parser routines
-- 
2.54.0