v: support dump(expr) (#9160)

cmd/tools/vcheck-md.v

@@ -204,7 +204,7 @@ fn (mut f MDFile) parse_line(lnumber int, line string) {
 	}
 }
 
-fn (mut f MDFile) dump() {
+fn (mut f MDFile) debug() {
 	for e in f.examples {
 		eprintln('f.path: $f.path | example: $e')
 	}

examples/dump_factorial.v

@@ -0,0 +1,10 @@
+fn factorial(n u32) u32 {
+	if dump(n <= 1) {
+		return dump(1)
+	}
+	return dump(n * factorial(n - 1))
+}
+
+fn main() {
+	println(factorial(5))
+}

vlib/v/ast/ast.v

@@ -11,10 +11,10 @@ pub type TypeDecl = AliasTypeDecl | FnTypeDecl | SumTypeDecl
 
 pub type Expr = AnonFn | ArrayDecompose | ArrayInit | AsCast | Assoc | AtExpr | BoolLiteral |
 	CTempVar | CallExpr | CastExpr | ChanInit | CharLiteral | Comment | ComptimeCall |
-	ComptimeSelector | ConcatExpr | EnumVal | FloatLiteral | GoExpr | Ident | IfExpr |
-	IfGuardExpr | IndexExpr | InfixExpr | IntegerLiteral | Likely | LockExpr | MapInit |
-	MatchExpr | None | OffsetOf | OrExpr | ParExpr | PostfixExpr | PrefixExpr | RangeExpr |
-	SelectExpr | SelectorExpr | SizeOf | SqlExpr | StringInterLiteral | StringLiteral |
+	ComptimeSelector | ConcatExpr | DumpExpr | EnumVal | FloatLiteral | GoExpr | Ident |
+	IfExpr | IfGuardExpr | IndexExpr | InfixExpr | IntegerLiteral | Likely | LockExpr |
+	MapInit | MatchExpr | None | OffsetOf | OrExpr | ParExpr | PostfixExpr | PrefixExpr |
+	RangeExpr | SelectExpr | SelectorExpr | SizeOf | SqlExpr | StringInterLiteral | StringLiteral |
 	StructInit | Type | TypeOf | UnsafeExpr
 
 pub type Stmt = AssertStmt | AssignStmt | Block | BranchStmt | CompFor | ConstDecl | DeferStmt |
@@ -1114,6 +1114,15 @@ pub mut:
 	expr_type table.Type
 }
 
+pub struct DumpExpr {
+pub:
+	expr Expr
+	pos  token.Position
+pub mut:
+	expr_type table.Type
+	cname     string // filled in the checker
+}
+
 pub struct Comment {
 pub:
 	text     string
@@ -1240,7 +1249,7 @@ pub fn (expr Expr) position() token.Position {
 			return expr.decl.pos
 		}
 		ArrayDecompose, ArrayInit, AsCast, Assoc, AtExpr, BoolLiteral, CallExpr, CastExpr, ChanInit,
-		CharLiteral, ConcatExpr, Comment, ComptimeCall, ComptimeSelector, EnumVal, FloatLiteral,
+		CharLiteral, ConcatExpr, Comment, ComptimeCall, ComptimeSelector, EnumVal, DumpExpr, FloatLiteral,
 		GoExpr, Ident, IfExpr, IndexExpr, IntegerLiteral, Likely, LockExpr, MapInit, MatchExpr,
 		None, OffsetOf, OrExpr, ParExpr, PostfixExpr, PrefixExpr, RangeExpr, SelectExpr, SelectorExpr,
 		SizeOf, SqlExpr, StringInterLiteral, StringLiteral, StructInit, Type, TypeOf, UnsafeExpr

vlib/v/checker/checker.v

@@ -3716,6 +3716,17 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
 		ast.ConcatExpr {
 			return c.concat_expr(mut node)
 		}
+		ast.DumpExpr {
+			node.expr_type = c.expr(node.expr)
+			if node.expr_type.idx() == table.void_type_idx {
+				c.error('dump expression can not be void', node.expr.position())
+				return table.void_type
+			}
+			tsym := c.table.get_type_symbol(node.expr_type)
+			c.table.dumps[int(node.expr_type)] = tsym.cname
+			node.cname = tsym.cname
+			return node.expr_type
+		}
 		ast.EnumVal {
 			return c.enum_val(mut node)
 		}

vlib/v/checker/tests/dump_of_void_expr.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/dump_of_void_expr.vv:3:6: error: dump expression can not be void
+    1 | fn abc() {}
+    2 | 
+    3 | dump(abc())
+      |      ~~~~~

vlib/v/checker/tests/dump_of_void_expr.vv

@@ -0,0 +1,3 @@
+fn abc() {}
+
+dump(abc())

vlib/v/fmt/fmt.v

@@ -900,6 +900,11 @@ pub fn (mut f Fmt) expr(node ast.Expr) {
 		ast.CTempVar {
 			eprintln('ast.CTempVar of $node.orig.str() should be generated/used only in cgen')
 		}
+		ast.DumpExpr {
+			f.write('dump(')
+			f.expr(node.expr)
+			f.write(')')
+		}
 		ast.AnonFn {
 			f.fn_decl(node.decl)
 		}

vlib/v/gen/c/cgen.v

@@ -266,6 +266,8 @@ pub fn gen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 			g.definitions.writeln('int _v_type_idx_${typ.cname}() { return $idx; };')
 		}
 	}
+	//
+	g.dump_expr_definitions()
 	// v files are finished, what remains is pure C code
 	g.gen_vlines_reset()
 	if g.pref.build_mode != .build_module {
@@ -2698,6 +2700,9 @@ fn (mut g Gen) expr(node ast.Expr) {
 				g.write("L'$node.val'")
 			}
 		}
+		ast.DumpExpr {
+			g.dump_expr(node)
+		}
 		ast.AtExpr {
 			g.comp_at(node)
 		}
@@ -2965,7 +2970,9 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 		g.write('(*(')
 	}
 	if sym.kind == .array_fixed {
-		assert node.field_name == 'len'
+		if node.field_name != 'len' {
+			g.error('field_name should be `len`', node.pos)
+		}
 		info := sym.info as table.ArrayFixed
 		g.write('$info.size')
 		return

vlib/v/gen/c/dumpexpr.v

@@ -0,0 +1,39 @@
+module c
+
+import v.ast
+
+fn (mut g Gen) dump_expr(node ast.DumpExpr) {
+	sexpr := ctoslit(node.expr.str())
+	fpath := cestring(g.file.path)
+	line := node.pos.line_nr + 1
+	if 'nop_dump' in g.pref.compile_defines {
+		g.expr(node.expr)
+		return
+	}
+	g.write(' _v_dump_expr_${node.cname}(${ctoslit(fpath)}, $line, $sexpr, ')
+	g.expr(node.expr)
+	g.write(' )')
+}
+
+fn (mut g Gen) dump_expr_definitions() {
+	if g.pref.build_mode == .build_module {
+		for _, cname in g.table.dumps {
+			g.definitions.writeln('$cname _v_dump_expr_${cname}(string fpath, int line, string sexpr, $cname x);')
+		}
+	} else {
+		for dump_type, cname in g.table.dumps {
+			to_string_fn_name := g.gen_str_for_type(dump_type)
+			g.definitions.writeln('$cname _v_dump_expr_${cname}(string fpath, int line, string sexpr, $cname x) {')
+			g.definitions.writeln('\teprint(${ctoslit('[')});')
+			g.definitions.writeln('\teprint(fpath);')
+			g.definitions.writeln('\teprint(${ctoslit(':')});')
+			g.definitions.writeln('\teprint(int_str(line));')
+			g.definitions.writeln('\teprint(${ctoslit('] ')});')
+			g.definitions.writeln('\teprint(sexpr);')
+			g.definitions.writeln('\teprint(${ctoslit(': ')});')
+			g.definitions.writeln('\teprintln(${to_string_fn_name}(x));')
+			g.definitions.writeln('\treturn x;')
+			g.definitions.writeln('}')
+		}
+	}
+}

vlib/v/gen/js/js.v

@@ -17,12 +17,12 @@ const (
 		'try', 'typeof', 'var', 'void', 'while', 'with', 'yield', 'Number', 'String', 'Boolean',
 		'Array', 'Map']
 	// used to generate type structs
-	v_types     = ['i8', 'i16', 'int', 'i64', 'byte', 'u16', 'u32', 'u64', 'f32', 'f64', 'int_literal',
-		'float_literal', 'size_t', 'bool', 'string', 'map', 'array']
-	shallow_equatables  = [table.Kind.i8, .i16, .int, .i64, .byte, .u16, .u32, .u64, .f32, .f64, .int_literal,
-		.float_literal, .size_t, .bool, .string]
-	tabs        = ['', '\t', '\t\t', '\t\t\t', '\t\t\t\t', '\t\t\t\t\t', '\t\t\t\t\t\t', '\t\t\t\t\t\t\t',
-		'\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t']
+	v_types            = ['i8', 'i16', 'int', 'i64', 'byte', 'u16', 'u32', 'u64', 'f32', 'f64',
+		'int_literal', 'float_literal', 'size_t', 'bool', 'string', 'map', 'array']
+	shallow_equatables = [table.Kind.i8, .i16, .int, .i64, .byte, .u16, .u32, .u64, .f32, .f64,
+		.int_literal, .float_literal, .size_t, .bool, .string]
+	tabs               = ['', '\t', '\t\t', '\t\t\t', '\t\t\t\t', '\t\t\t\t\t', '\t\t\t\t\t\t',
+		'\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t', '\t\t\t\t\t\t\t\t\t']
 )
 
 struct Namespace {
@@ -115,7 +115,7 @@ pub fn gen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	mut out := g.hashes() + g.definitions.str()
 	// equality check for js objects
 	// TODO: Fix msvc bug that's preventing $embed_file('fast_deep_equal.js')
-	//unsafe {
+	// unsafe {
 	//	mut eq_fn := $embed_file('fast_deep_equal.js')
 	//	out += eq_fn.data().vstring()
 	//}
@@ -447,6 +447,9 @@ fn (mut g JsGen) expr(node ast.Expr) {
 		ast.CTempVar {
 			g.write('/* ast.CTempVar: node.name */')
 		}
+		ast.DumpExpr {
+			g.write('/* ast.DumpExpr: $node.expr */')
+		}
 		ast.AnonFn {
 			g.gen_fn_decl(node.decl)
 		}
@@ -689,10 +692,12 @@ fn (mut g JsGen) gen_assign_stmt(stmt ast.AssignStmt) {
 			} else {
 				g.write(' $op ')
 				// TODO: Multiple types??
-				should_cast := g.table.type_kind(stmt.left_types.first()) in shallow_equatables
+				should_cast := g.table.type_kind(stmt.left_types.first()) in js.shallow_equatables
 				if should_cast {
 					g.cast_stack << stmt.left_types.first()
-					if g.file.mod.name == 'builtin' { g.write('new ') }
+					if g.file.mod.name == 'builtin' {
+						g.write('new ')
+					}
 					g.write('${g.typ(stmt.left_types.first())}(')
 				}
 				g.expr(val)
@@ -845,7 +850,9 @@ fn (mut g JsGen) gen_method_decl(it ast.FnDecl) {
 	}
 	g.fn_args(args, it.is_variadic)
 	if it.is_method {
-		if args.len > 0 { g.write(', ') }
+		if args.len > 0 {
+			g.write(', ')
+		}
 		g.write('${it.params[0].name} = this')
 	}
 	g.writeln(') {')
@@ -926,13 +933,23 @@ fn (mut g JsGen) gen_for_in_stmt(it ast.ForInStmt) {
 		if val !in ['', '_'] {
 			g.write('\tconst $val = ')
 			if it.kind == .string {
-				if g.file.mod.name == 'builtin' { g.write('new ') }
+				if g.file.mod.name == 'builtin' {
+					g.write('new ')
+				}
 				g.write('byte(')
 			}
 			g.expr(it.cond)
-			g.write(if it.kind == .array { '.arr' } else if it.kind == .string { '.str' } else { '.val' })
+			g.write(if it.kind == .array {
+				'.arr'
+			} else if it.kind == .string {
+				'.str'
+			} else {
+				'.val'
+			})
 			g.write('[$i]')
-			if it.kind == .string { g.write(')') }
+			if it.kind == .string {
+				g.write(')')
+			}
 			g.writeln(';')
 		}
 		g.stmts(it.stmts)
@@ -1369,11 +1386,13 @@ fn (mut g JsGen) gen_infix_expr(it ast.InfixExpr) {
 	r_sym := g.table.get_type_symbol(it.right_type)
 
 	is_not := it.op in [.not_in, .not_is, .ne]
-	if is_not { g.write('!(') }
+	if is_not {
+		g.write('!(')
+	}
 
 	if it.op == .eq || it.op == .ne {
 		// Shallow equatables
-		if l_sym.kind in shallow_equatables && r_sym.kind in shallow_equatables {
+		if l_sym.kind in js.shallow_equatables && r_sym.kind in js.shallow_equatables {
 			g.expr(it.left)
 			g.write('.eq(')
 			g.expr(it.right)
@@ -1404,7 +1423,9 @@ fn (mut g JsGen) gen_infix_expr(it ast.InfixExpr) {
 			'.includes('
 		})
 		g.expr(it.left)
-		if l_sym.kind == .string { g.write('.str') }
+		if l_sym.kind == .string {
+			g.write('.str')
+		}
 		g.write(')')
 	} else if it.op in [.key_is, .not_is] { // foo is Foo
 		g.expr(it.left)
@@ -1423,7 +1444,7 @@ fn (mut g JsGen) gen_infix_expr(it ast.InfixExpr) {
 			g.cast_stack << greater_typ
 		}
 		g.expr(it.left)
-		g.write(' ${it.op} ')
+		g.write(' $it.op ')
 		g.expr(it.right)
 
 		if is_arithmetic && needs_cast {
@@ -1432,7 +1453,9 @@ fn (mut g JsGen) gen_infix_expr(it ast.InfixExpr) {
 		}
 	}
 
-	if is_not { g.write(')') }
+	if is_not {
+		g.write(')')
+	}
 }
 
 fn (mut g JsGen) greater_typ(left table.Type, right table.Type) table.Type {
@@ -1560,7 +1583,7 @@ fn (mut g JsGen) gen_string_literal(it ast.StringLiteral) {
 		if g.file.mod.name == 'builtin' {
 			g.write('new ')
 		}
-		g.write("string(")
+		g.write('string(')
 	}
 	g.write("'$text'")
 	if should_cast {
@@ -1651,7 +1674,7 @@ fn (mut g JsGen) gen_integer_literal_expr(it ast.IntegerLiteral) {
 	// TODO: call.language always seems to be "v", parser bug?
 	if g.call_stack.len > 0 {
 		call := g.call_stack[g.call_stack.len - 1]
-		//if call.language == .js {
+		// if call.language == .js {
 		for t in call.args {
 			if t.expr is ast.IntegerLiteral {
 				if t.expr == it {
@@ -1685,7 +1708,7 @@ fn (mut g JsGen) gen_float_literal_expr(it ast.FloatLiteral) {
 	// TODO: call.language always seems to be "v", parser bug?
 	if g.call_stack.len > 0 {
 		call := g.call_stack[g.call_stack.len - 1]
-		//if call.language == .js {
+		// if call.language == .js {
 		for i, t in call.args {
 			if t.expr is ast.FloatLiteral {
 				if t.expr == it {

vlib/v/markused/walker.v

@@ -180,6 +180,9 @@ fn (mut w Walker) expr(node ast.Expr) {
 				w.stmts(node.vweb_tmpl.stmts)
 			}
 		}
+		ast.DumpExpr {
+			w.expr(node.expr)
+		}
 		ast.GoExpr {
 			w.expr(node.go_stmt.call_expr)
 		}

vlib/v/parser/parser.v

@@ -670,6 +670,7 @@ pub fn (mut p Parser) stmt(is_top_level bool) ast.Stmt {
 				p.label_names << name
 				p.next()
 				if p.tok.kind == .key_for {
+					for_pos := p.tok.position()
 					mut stmt := p.stmt(is_top_level)
 					match mut stmt {
 						ast.ForStmt {
@@ -685,7 +686,7 @@ pub fn (mut p Parser) stmt(is_top_level bool) ast.Stmt {
 							return stmt
 						}
 						else {
-							assert false
+							p.error_with_pos('unknown kind of For statement', for_pos)
 						}
 					}
 				}
@@ -1031,7 +1032,7 @@ fn (mut p Parser) parse_multi_expr(is_top_level bool) ast.Stmt {
 			if node !is ast.CallExpr && (is_top_level || p.tok.kind != .rcbr)
 				&& node !is ast.PostfixExpr && !(node is ast.InfixExpr
 				&& (node as ast.InfixExpr).op in [.left_shift, .arrow]) && node !is ast.ComptimeCall
-				&& node !is ast.SelectorExpr {
+				&& node !is ast.SelectorExpr && node !is ast.DumpExpr {
 				p.error_with_pos('expression evaluated but not used', node.position())
 				return ast.Stmt{}
 			}

vlib/v/parser/pratt.v

@@ -214,6 +214,17 @@ pub fn (mut p Parser) expr(precedence int) ast.Expr {
 				pos: spos.extend(p.tok.position())
 			}
 		}
+		.key_dump {
+			spos := p.tok.position()
+			p.next()
+			p.check(.lpar)
+			expr := p.expr(0)
+			p.check(.rpar)
+			node = ast.DumpExpr{
+				expr: expr
+				pos: spos.extend(p.tok.position())
+			}
+		}
 		.key_offsetof {
 			pos := p.tok.position()
 			p.next() // __offsetof

vlib/v/table/table.v

@@ -12,6 +12,7 @@ pub mut:
 	types         []TypeSymbol
 	type_idxs     map[string]int
 	fns           map[string]Fn
+	dumps         map[int]string // needed for efficiently generating all _v_dump_expr_TNAME() functions
 	imports       []string       // List of all imports
 	modules       []string       // Topologically sorted list of all modules registered by the application
 	cflags        []cflag.CFlag

vlib/v/tests/inout/dump_expression.out

@@ -0,0 +1,7 @@
+[vlib/v/tests/inout/dump_expression.vv:2] 1: 1
+[vlib/v/tests/inout/dump_expression.vv:7] 'a': a
+[vlib/v/tests/inout/dump_expression.vv:20] point: Point{
+    x: 1
+    y: 2
+    z: 3
+}

vlib/v/tests/inout/dump_expression.vv

@@ -0,0 +1,29 @@
+fn dump_of_int() {
+	x := dump(1) + 1
+	assert x == 2
+}
+
+fn dump_of_string() {
+	x := dump('a') + 'b'
+	assert x == 'ab'
+}
+
+struct Point {
+mut:
+	x int
+	y int
+	z int
+}
+
+fn dump_of_struct() {
+	point := Point{1, 2, 3}
+	mut x := dump(point)
+	x.x += 100
+	assert x == Point{101, 2, 3}
+}
+
+fn main() {
+	dump_of_int()
+	dump_of_string()
+	dump_of_struct()
+}

vlib/v/token/token.v

@@ -117,6 +117,7 @@ pub enum Kind {
 	key_true
 	key_type
 	key_typeof
+	key_dump
 	key_orelse
 	key_union
 	key_pub
@@ -274,6 +275,7 @@ fn build_token_str() []string {
 	s[Kind.key_import] = 'import'
 	s[Kind.key_unsafe] = 'unsafe'
 	s[Kind.key_typeof] = 'typeof'
+	s[Kind.key_dump] = 'dump'
 	s[Kind.key_enum] = 'enum'
 	s[Kind.key_interface] = 'interface'
 	s[Kind.key_pub] = 'pub'

vlib/v/vmod/vmod.v

@@ -42,7 +42,7 @@ pub fn new_mod_file_cacher() &ModFileCacher {
 	return &ModFileCacher{}
 }
 
-pub fn (mcache &ModFileCacher) dump() {
+pub fn (mcache &ModFileCacher) debug() {
 	$if debug {
 		eprintln('ModFileCacher DUMP:')
 		eprintln('	 ModFileCacher.cache:')