compiler2: proof of concept cgen

vlib/compiler/fn.v

@@ -980,6 +980,9 @@ fn (p mut Parser) fn_args(f mut Fn) {
 			p.next()
 		}
 	}
+	//if types_only && p.peek() == .lcbr {
+		//println('wtf')
+	//}
 }
 
 // foo *(1, 2, 3, mut bar)*

vlib/compiler2/ast/ast.v

@@ -10,15 +10,19 @@ import (
 
 struct Foo {}
 
-// pub type Expr = Foo | IfExpr | BinaryExpr | IntegerExpr
-pub type Expr = Foo | IfExpr | BinaryExpr | ScalarExpr | UnaryExpr
+pub type Expr = Foo | IfExpr | BinaryExpr | ScalarExpr | UnaryExpr |
+	StringLiteral  | IntegerExpr
+pub type Stmt = Foo | VarDecl
 
-/*
 pub struct IntegerExpr {
 pub:
 	val int
 }
-*/
+
+pub struct StringLiteral {
+pub:
+	val string
+}
 
 /*
 pub enum Expr {
@@ -28,10 +32,24 @@ pub enum Expr {
 }
 */
 
+/*
 pub struct Stmt {
 	pos int
 	//end int
 }
+*/
+
+pub struct VarDecl {
+pub:
+	name string
+	expr Expr
+
+}
+
+pub struct Program {
+pub:
+	exprs []Expr
+}
 
 // A single identifier
 struct Ident {

vlib/compiler2/cgen/cgen.v

@@ -0,0 +1,82 @@
+module cgen
+
+import (
+	strings
+	compiler2.ast
+)
+
+struct Gen {
+	out strings.Builder
+
+}
+
+pub fn gen(program ast.Program) {
+	mut g := Gen{out:strings.new_builder(100)}
+	for expr in program.exprs {
+		g.expr(expr)
+		g.writeln('')
+	}
+	println(g.out.str())
+}
+
+pub fn (g &Gen) save() {
+
+}
+
+pub fn (g mut Gen) write(s string) {
+	g.out.write(s)
+}
+
+pub fn (g mut Gen) writeln(s string) {
+	g.out.writeln(s)
+}
+
+struct Type {
+	name string
+}
+
+const (
+	string_type = Type{'string'}
+	int_type = Type{'int'}
+	void_type = Type{'void'}
+)
+
+fn (g mut Gen) expr(node ast.Expr) Type {
+	//println('cgen expr()')
+	match node {
+		ast.IntegerExpr {
+			g.write(it.val.str())
+			return int_type
+		}
+		ast.StringLiteral {
+			g.write('"$it.val"')
+			return string_type
+		}
+		ast.BinaryExpr {
+			typ := g.expr(it.left)
+			match it.op {
+				.plus {	g.write(' + ')	}
+				.minus {	g.write(' - ')	}
+				.mul {	g.write(' * ')	}
+				.div {	g.write(' / ')	}
+				else {}
+			}
+			typ2 := g.expr(it.right)
+			if typ.name != typ2.name {
+				println('bad types $typ.name $typ2.name')
+			}
+			return typ
+		}
+		ast.VarDecl {
+			g.write('var $it.name = ')
+			g.expr(it.expr)
+			g.writeln(';')
+			return void_type
+		}
+		else {
+			println('bad node')
+		}
+	}
+	return void_type
+}
+

vlib/compiler2/parser/parser.v

@@ -12,8 +12,8 @@ import (
 struct Parser {
 	scanner &scanner.Scanner
 mut:
-	tok token.Token
-	lit string
+	tok     token.Token
+	lit     string
 }
 
 pub fn parse_expr(text string) ast.Expr {
@@ -28,10 +28,21 @@ pub fn parse_expr(text string) ast.Expr {
 	return p.expr(token.lowest_prec)
 }
 
+pub fn parse_stmt(text string) ast.Stmt {
+	mut s := scanner.new_scanner(text)
+	res := s.scan()
+	mut p := Parser{
+		scanner: s
+		tok: res.tok
+		lit: res.lit
+	}
+	return p.stmt()
+}
+
 fn (p mut Parser) next() {
 	res := p.scanner.scan()
 	p.tok = res.tok
-	//println(p.tok.str())
+	// println(p.tok.str())
 	p.lit = res.lit
 }
 
@@ -41,37 +52,76 @@ pub fn (p mut Parser) expr(rbp int) ast.Expr {
 	tok := p.tok
 	lit := p.lit
 	p.next()
-	mut left := ast.Expr{}
+	mut node := ast.Expr{
+	}
 	match tok {
 		.lpar {
-			left = p.expr(0)
+			node = p.expr(0)
 			if p.tok != .rpar {
-				panic("Parse Error: expected )")
+				panic('Parse Error: expected )')
 			}
 			p.next()
 		}
 		else {
 			// TODO: fix bug. note odd conditon instead of else if (same below)
 			if tok.is_scalar() {
-				left = ast.ScalarExpr{val: lit, typ: tok}
+				node = ast.ScalarExpr{
+					val: lit
+					typ: tok
+				}
 			}
 			if !tok.is_scalar() && tok.is_unary() {
-				left = ast.UnaryExpr{left: p.expr(token.highest_prec), op: tok}
+				node = ast.UnaryExpr{
+					left: p.expr(token.highest_prec)
+					op: tok
+				}
 			}
-		}
-	}
-
+		}}
 	// left binding power
 	for rbp < p.tok.precedence() {
 		tok2 := p.tok
 		p.next()
 		// left denotation (infix)
 		if tok2.is_right_assoc() {
-			left = ast.BinaryExpr{left: left, op: tok2, right: p.expr(tok2.precedence() - 1)}
+			node = ast.BinaryExpr{
+				left: node
+				op: tok2
+				right: p.expr(tok2.precedence() - 1)
+			}
 		}
 		if !tok2.is_right_assoc() && tok2.is_left_assoc() {
-			left = ast.BinaryExpr{left: left, op: tok2, right: p.expr(tok2.precedence())}
+			node = ast.BinaryExpr{
+				left: node
+				op: tok2
+				right: p.expr(tok2.precedence())
+			}
 		}
 	}
-	return left
+	return node
+}
+
+fn (p mut Parser) stmt() ast.Stmt {
+	if p.tok == .name {
+		name := p.lit
+		p.next()
+		if p.tok == .decl_assign {
+			p.next()
+			return ast.VarDecl{
+				name: name
+				expr: p.expr(token.lowest_prec)
+			}
+		}
+	}
+	/*
+	match node {
+		Ident {
+
+
+		}
+
+	}
+	*/
+
+	return ast.VarDecl{
+	}
 }

vlib/compiler2/parser/parser_test.v

@@ -1,6 +1,9 @@
 module parser
 
-import compiler2.ast
+import (
+	compiler2.ast
+	compiler2.cgen
+)
 
 fn test_parser() {
 	//expr := ast.IntegerExpr {val:10}
@@ -62,4 +65,17 @@ fn walk(node ast.Expr) {
 		}
 		else { }
 	}
+/*
+	//expr := parse_expr('3 + 7 * 2')
+	expr := parse_stmt('a := 3 + "f"')
+	program := ast.Program{
+		exprs: [
+			expr,
+			//parse_expr('2 * 2'),
+		]
+	}
+	cgen.gen(program)
+	//cgen.save()
+	*/
 }
+

vlib/strings/builder_c.v

@@ -29,6 +29,9 @@ pub fn (b mut Builder) write_b(data byte) {
 }
 
 pub fn (b mut Builder) write(s string) {
+	if s == '' {
+		return
+	}
 	b.buf.push_many(s.str, s.len)
 	// for c in s {
 	// b.buf << c