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a[start..end] slicing

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This commit is contained in:
Alexander Medvednikov 2019-10-26 21:58:26 +03:00
parent 678ce54e70
commit 570a7aaaf3
3 changed files with 33 additions and 11 deletions
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18
vlib/compiler/gen_c.v
View File

@ -169,7 +169,7 @@ fn types_to_c(types []Type, table &Table) string {
return sb.str()
}
fn (p mut Parser) index_get(typ string, fn_ph int, cfg IndexCfg) {
fn (p mut Parser) index_get(typ string, fn_ph int, cfg IndexConfig) {
// Erase var name we generated earlier: "int a = m, 0"
// "m, 0" gets killed since we need to start from scratch. It's messy.
// "m, 0" is an index expression, save it before deleting and insert later in map_get()
@ -195,15 +195,21 @@ fn (p mut Parser) index_get(typ string, fn_ph int, cfg IndexCfg) {
p.gen('$index_expr ]')
}
else {
if cfg.is_ptr {
p.gen('( *($typ*) array_get(* $index_expr) )')
} else {
p.gen('( *($typ*) array_get($index_expr) )')
amp := if cfg.is_ptr { '&' } else { '' }
if cfg.is_slice {
p.gen(' array_slice($amp $index_expr) ')
}
else {
p.gen('( *($typ*) array_get($amp $index_expr) )')
}
}
}
else if cfg.is_str && !p.builtin_mod {
p.gen('string_at($index_expr)')
if cfg.is_slice {
p.gen('string_substr($index_expr)')
} else {
p.gen('string_at($index_expr)')
}
}
// Zero the string after map_get() if it's nil, numbers are automatically 0
// This is ugly, but what can I do without generics?

2
vlib/compiler/gen_js.v
View File

@ -70,7 +70,7 @@ fn types_to_c(types []Type, table &Table) string {
return sb.str()
}
fn (p mut Parser) index_get(typ string, fn_ph int, cfg IndexCfg) {
fn (p mut Parser) index_get(typ string, fn_ph int, cfg IndexConfig) {
p.cgen.cur_line = p.cgen.cur_line.replace(',', '[') + ']'
}

24
vlib/compiler/parser.v
View File

@ -2091,6 +2091,7 @@ fn (p mut Parser) index_expr(typ_ string, fn_ph int) string {
is_arr0 := typ.starts_with('array_')
is_arr := is_arr0 || typ == 'array'
is_ptr := typ == 'byte*' || typ == 'byteptr' || typ.contains('*')
mut is_slice := false
is_indexer := p.tok == .lsbr
mut close_bracket := false
index_error_tok_pos := p.token_idx
@ -2163,6 +2164,19 @@ fn (p mut Parser) index_expr(typ_ string, fn_ph int) string {
if p.cgen.cur_line.right(index_pos).replace(' ', '').int() < 0 {
p.error('cannot access negative array index')
}
if p.tok == .dotdot {
if is_arr {
typ = 'array_' + typ
} else if is_str {
typ = 'string'
} else {
p.error('slicing is supported by arrays and strings only')
}
is_slice = true
p.next()
p.gen(',')
p.check_types(p.expression(), 'int')
}
}
else {
T := p.table.find_type(p.expression())
@ -2197,6 +2211,7 @@ fn (p mut Parser) index_expr(typ_ string, fn_ph int) string {
return typ
}
}
// `m[key] = val`
// TODO move this from index_expr()
if (p.tok == .assign && !p.is_sql) || p.tok.is_assign() {
if is_indexer && is_str && !p.builtin_mod {
@ -2216,26 +2231,27 @@ fn (p mut Parser) index_expr(typ_ string, fn_ph int) string {
// else if p.pref.is_verbose && p.assigned_var != '' {
// p.error('didnt assign')
// }
// m[key]. no =, just a getter
// `m[key]`. no =, just a getter
else if (is_map || is_arr || (is_str && !p.builtin_mod)) && is_indexer {
p.index_get(typ, fn_ph, IndexCfg{
p.index_get(typ, fn_ph, IndexConfig{
is_arr: is_arr
is_map: is_map
is_ptr: is_ptr
is_str: is_str
is_slice: is_slice
})
}
// else if is_arr && is_indexer{}
return typ
}
struct IndexCfg {
struct IndexConfig {
is_map bool
is_str bool
is_ptr bool
is_arr bool
is_arr0 bool
is_slice bool
}
// for debugging only