basic: more parser wip

assets/basic.js

@@ -1602,28 +1602,40 @@ bF._recurseApplyAST = function(tree, action) {
     }
 }
 /** EBNF notation:
+line = linenumber , stmt , {":" , stmt} ;
+linenumber = digits ;
+
 stmt =  
-      "IF" , equation , "THEN" , stmt , ["ELSE" , stmt]
+      "IF" , if_equation , "THEN" , stmt , ["ELSE" , stmt]
     | "DEFUN" , [lit] , "(" , [lit , {" , " , lit}] , ")" , "=" , stmt
-    | "ON" , lit , function , equation , [{"," , equation}]
+    | "ON" , lit , lit , equation , {"," , equation}
-    | function , [equation , {argsep , equation}]
+    | function_call
-    | function , "(" , [equation , {argsep , equation}] , ")"
-    | equation
     | "(" , stmt , ")" ;
     
-equation = lit , op , lit
+function_call =
-    | op_uni , lit
+      lit
+    | lit , function_call , {argsep , function_call}
+    | lit , "(" , [function_call , {argsep , function_call}] , ")"
+    | equation
+    
+equation = equation , op , equation
+    | op_uni , equation
     | lit
     | "(" , equation , ")"
 
+if_equation = if_equation , op - ("=") , if_equation
+    | op_uni , if_equation
+    | lit
+    | "(" , if_equation , ")"
+    
 (* don't bother looking at these, because you already know the stuff *)    
     
 function = lit ;
 argsep = ","|";" ;
-lit = alph , [digits] | num | string ;
+lit = alph , [digits] | num | string ; (* example: "MyVar_2" *)
 op = "^" | "*" | "/" | "MOD" | "+" | "-" | "<<" | ">>" | "<" | ">" | "<="
     | "=<" | ">=" | "=>" | "==" | "<>" | "><" | "BAND" | "BXOR" | "BOR"
-    | "AND" | "OR" | "TO" | "STEP" | "!" | "~" | "#" | "=" | ":" ;
+    | "AND" | "OR" | "TO" | "STEP" | "!" | "~" | "#" | "=" ;
 op_uni = "-" | "+" ;
 
 alph = letter | letter , alph ;

assets/tbas/parser_wip.js

@@ -24,6 +24,8 @@ bF._parseStmt = function(lnum, tokens, states, recDepth) {
     treeHead.astDepth = recDepth;
     treeHead.astLnum = lnum;
     
+    // ## case for:
+    //    "IF" , if_equation , "THEN" , stmt , ["ELSE" , stmt]
     if ("IF" == headTkn && "lit" == headSta) {
         // find nearest THEN and ELSE but also take parens into account
         let thenPos = -1;
@@ -59,14 +61,43 @@ bF._parseStmt = function(lnum, tokens, states, recDepth) {
         // "THEN" not found, raise error!
         if (thenPos == -1) throw ParserError("IF without THEN in " + lnum);
         
-        // TODO gotta go home :)
+        treeHead.astValue = "IF";
+        treeHead.astType = "function";
+        
+        treeHead.astLeaves[0] = bF._parseEquation(lnum,
+            tokens.slice(1, thenPos),
+            states.slice(1, thenPos),
+            recDepth + 1,
+            true // if_equation mode
+        );
+        treeHead.astLeaves[1] = bF._parseStmt(lnum,
+            tokens.slice(thenPos + 1, (elsePos != -1) ? elsePos : tokens.length),
+            states.slice(thenPos + 1, (elsePos != -1) ? elsePos : tokens.length),
+            recDepth + 1
+        );
+        if (elsePos != -1)
+            treeHead.astLeaves[2] = bF._parseStmt(lnum,
+                tokens.slice(elsePos + 1, tokens.length),
+                states.slice(elsePos + 1, tokens.length),
+                recDepth + 1
+            );
+        
+        return treeHead;
     }
+
+    // ## case for:
+    //    ???
+        
+    // TODO
+   
 }
 /** Parses following EBNF rule:
  * lit (* which is parsed by the tokeniser already *)
  * @return: BasicAST
  */
 bF._parseLit = function(lnum, tokens, states, recDepth) {
+    if (tokens.length > 1) throw ParserError();
+    
     let treeHead = new BasicAST();
     treeHead.astDepth = recDepth;
     treeHead.astLnum = lnum;
@@ -82,7 +113,7 @@ bF._parseLit = function(lnum, tokens, states, recDepth) {
         }
         // else, screw it
         else {
-            throw lang.syntaxfehler(lnum, "TRAP_LITERALLY_LITERAL");
+            throw ParserError("TRAP_LITERALLY_LITERAL");
         }
     }
 
@@ -98,7 +129,7 @@ bF._parseLit = function(lnum, tokens, states, recDepth) {
  * @return: BasicAST
  */
 bF._EquationIllegalTokens = ["IF","THEN","ELSE","DEFUN","ON"];
-bF._parseEquation = function(lnum, tokens, states, recDepth) {
+bF._parseEquation = function(lnum, tokens, states, recDepth, ifMode) {
     // scan for operators with highest precedence, use rightmost one if multiple were found
     let topmostOp;
     let topmostOpPrc = 0;
@@ -156,6 +187,10 @@ bF._parseEquation = function(lnum, tokens, states, recDepth) {
     if (topmostOp !== undefined) {
         if (_debugSyntaxAnalysis) serial.println("operator: "+topmostOp+", pos: "+operatorPos);
 
+        if (ifMode && topmostOp == "=") throw lang.syntaxfehler(lnum, "'=' used on IF, did you mean '=='?");
+        if (ifMode && topmostOp == ":") throw lang.syntaxfehler(lnum, "':' used on IF");
+        
+        
         // this is the AST we're going to build up and return
         // (other IF clauses don't use this)
         let treeHead = new BasicAST();
@@ -188,7 +223,7 @@ bF._parseEquation = function(lnum, tokens, states, recDepth) {
     // ## case for:
     //    lit
     let headTkn = tokens[0].toUpperCase();
-    if (!bF._EquationIllegalTokens.includes(headTkn)) {
+    if (!bF._EquationIllegalTokens.includes(headTkn) && tokens.length == 1) {
         return bF._parseLit(lnum, tokens, states, recDepth + 1);
     }
     

assets/tbas/syntax.txt

@@ -1,25 +1,37 @@
+line = linenumber , stmt , {":" , stmt} ;
+linenumber = digits ;
+
 stmt =  
-      "IF" , equation , "THEN" , stmt , ["ELSE" , stmt]
+      "IF" , if_equation , "THEN" , stmt , ["ELSE" , stmt]
     | "DEFUN" , [lit] , "(" , [lit , {" , " , lit}] , ")" , "=" , stmt
-    | "ON" , lit , function , equation , [{"," , equation}]
+    | "ON" , lit , lit , equation , {"," , equation}
-    | function , [equation , {argsep , equation}]
+    | function_call
-    | function , "(" , [equation , {argsep , equation}] , ")"
-    | equation 
     | "(" , stmt , ")" ;
     
+function_call =
+      lit
+    | lit , function_call , {argsep , function_call}
+    | lit , "(" , [function_call , {argsep , function_call}] , ")"
+    | equation
+    
 equation = equation , op , equation
     | op_uni , equation
     | lit
     | "(" , equation , ")"
 
+if_equation = if_equation , op - ("=") , if_equation
+    | op_uni , if_equation
+    | lit
+    | "(" , if_equation , ")"
+    
 (* don't bother looking at these, because you already know the stuff *)    
     
 function = lit ;
 argsep = ","|";" ;
-lit = alph , [digits] | num | string ;
+lit = alph , [digits] | num | string ; (* example: "MyVar_2" *)
 op = "^" | "*" | "/" | "MOD" | "+" | "-" | "<<" | ">>" | "<" | ">" | "<="
     | "=<" | ">=" | "=>" | "==" | "<>" | "><" | "BAND" | "BXOR" | "BOR"
-    | "AND" | "OR" | "TO" | "STEP" | "!" | "~" | "#" | "=" | ":" ;
+    | "AND" | "OR" | "TO" | "STEP" | "!" | "~" | "#" | "=" ;
 op_uni = "-" | "+" ;
 
 alph = letter | letter , alph ;
@@ -47,3 +59,24 @@ hexdigit = "A" | "B" | "C" | "D" | "E" | "F" | "a" | "b"
 bindigit = "0" | "1" ;
 
 (* all possible token states: lit num op bool qot paren sep *)
+
+
+IF
+1. cond
+2. true
+[3. false]
+
+DEFUN
+1. funcname
+    1. arg0
+    [2. arg1]
+    [3. argN...]
+2. stmt
+
+ON
+1. varname
+2. functionname
+3. arg0
+[4. arg1]
+[5. argN...]
+