cgen: use *char in all functions with *char args to avoid warnings

CONTRIBUTING.md

@@ -4,7 +4,7 @@ I tried making the code of the compiler and vlib as simple and readable as possi
 
 The compiler itself is located in `compiler/`
 
-It has only 8 files (soon to be 7):
+The main files are:
 
 1. `main.v` The entry point.
 - V figures out the build mode.

compiler/fn.v

@@ -746,14 +746,17 @@ fn (p mut Parser) fn_args(f mut Fn) {
 
 // foo *(1, 2, 3, mut bar)*
 fn (p mut Parser) fn_call_args(f mut Fn) &Fn {
-	// p.gen('(')
 	// println('fn_call_args() name=$f.name args.len=$f.args.len')
 	// C func. # of args is not known
-	// if f.name.starts_with('c_') {
 	p.check(.lpar)
 	if f.is_c {
 		for p.tok != .rpar {
-			p.bool_expression()
+			ph := p.cgen.add_placeholder()
+			typ := p.bool_expression()
+			// Cast V byteptr to C char* (byte is unsigned in V, that led to C warnings)
+			if typ == 'byte*' {
+				p.cgen.set_placeholder(ph, '(char*)')
+			}	
 			if p.tok == .comma {
 				p.gen(', ')
 				p.check(.comma)

compiler/parser.v

@@ -3171,6 +3171,7 @@ fn (p mut Parser) switch_statement() {
 	}
 	p.cgen.start_tmp()
 	typ := p.bool_expression()
+	is_str := typ == 'string'
 	expr := p.cgen.end_tmp()
 	p.check(.lcbr)
 	mut i := 0
@@ -3198,13 +3199,16 @@ fn (p mut Parser) switch_statement() {
 		mut got_comma := false
 		for {
 			if got_comma {
-				p.gen(') ||  ')
+				if is_str {
+					p.gen(')')
+				}	
+				p.gen(' || ')
 			}
 			if typ == 'string' {
 				p.gen('string_eq($expr, ')
 			}
 			else {
-				p.gen('($expr == ')
+				p.gen('$expr == ')
 			}
 			if p.tok == .key_case || p.tok == .key_default {
 				p.check(p.tok)
@@ -3222,7 +3226,10 @@ fn (p mut Parser) switch_statement() {
 		else {
 			p.check(.arrow)
 		}
-		p.gen(')) {')
+		if is_str {
+			p.gen(')')
+		}
+		p.gen(') {')
 		p.genln('/* case */')
 		p.statements()
 		all_cases_return = all_cases_return && p.returns

vlib/os/os.v

@@ -77,12 +77,7 @@ fn parse_windows_cmd_line(cmd byteptr) []string {
 // read_file reads the file in `path` and returns the contents.
 pub fn read_file(path string) ?string {
 	mode := 'rb'
-	mut fp := &C.FILE{!}
-	$if windows {
-		fp = C._wfopen(path.to_wide(), mode.to_wide())
-	} $else {
-		fp = C.fopen(path.str, mode.str)
-	}
+	mut fp := vfopen(path, mode)
 	if isnil(fp) {
 		return error('failed to open file "$path"')
 	}
@@ -103,7 +98,7 @@ pub fn file_size(path string) int {
 	$if windows {
 		C._wstat(path.to_wide(), &s)
 	} $else {
-		C.stat(path.str, &s)
+		C.stat(*char(path.str), &s)
 	}
 	return s.st_size
 }
@@ -112,7 +107,15 @@ pub fn mv(old, new string) {
 	$if windows {
 		C._wrename(old.to_wide(), new.to_wide())
 	} $else {
-		C.rename(old.str, new.str)
+		C.rename(*char(old.str), *char(new.str))
+	}
+}
+
+fn vfopen(path, mode string) *C.FILE {
+	$if windows {
+		return C._wfopen(path.to_wide(), mode.to_wide())
+	} $else {
+		return C.fopen(*char(path.str), *char(mode.str))
 	}
 }	
 
@@ -124,12 +127,7 @@ pub fn read_lines(path string) []string {
 	mut buf := malloc(buf_len)
 
 	mode := 'rb'
-	mut fp := &C.FILE{!}
-	$if windows {
-		fp = C._wfopen(path.to_wide(), mode.to_wide())
-	} $else {
-		fp = C.fopen(path.str, mode.str)
-	}
+	mut fp := vfopen(path, mode)
 	if isnil(fp) {
 		// TODO
 		// return error('failed to open file "$path"')
@@ -183,7 +181,7 @@ pub fn open(path string) ?File {
 	} $else {
 		cpath := path.str
 		file = File {
-			cfile: C.fopen(cpath, 'rb')
+			cfile: C.fopen(*char(cpath), 'rb')
 		}
 	}
 	if isnil(file.cfile) {
@@ -204,7 +202,7 @@ pub fn create(path string) ?File {
 	} $else {
 		cpath := path.str
 		file = File {
-			cfile: C.fopen(cpath, 'wb')
+			cfile: C.fopen(*char(cpath), 'wb')
 		}
 	}
 	if isnil(file.cfile) {
@@ -224,7 +222,7 @@ pub fn open_append(path string) ?File {
 	} $else {
 		cpath := path.str
 		file = File {
-			cfile: C.fopen(cpath, 'ab')
+			cfile: C.fopen(*char(cpath), 'ab')
 		}
 	}
 	if isnil(file.cfile) {
@@ -306,7 +304,7 @@ pub fn exec(cmd string) ?Result {
 	}
 	buf := [1000]byte
 	mut res := ''
-	for C.fgets(buf, 1000, f) != 0 {
+	for C.fgets(*char(buf), 1000, f) != 0 {
 		res += tos(buf, vstrlen(buf))
 	}
 	res = res.trim_space()
@@ -342,7 +340,7 @@ pub fn getenv(key string) string {
 		}
 		return string_from_wide(s)
 	} $else {
-		s := C.getenv(key.str)
+		s := *byte(C.getenv(key.str))
 		if isnil(s) {
 			return ''
 		}