Unserialize parts of a tree-sitter tree

The [[ operator works similarly to the combination of ts_tree_select() and ts_tree_unserialize(), but it might be more readable.

Usage

# S3 method for class 'ts_tree'
x[[i, ...]]

Arguments

x

A ts_tree object.

i

Selection expressions in a list, see details in ts_tree_select().

...

Additional arguments, passed to ts_tree_select().

Value

List of R objects, with one entry for each selected element.

Details

The following two expressions are equivalent:

 

ts_tree_select(tree, <selectors>) |> ts_tree_unserialize()

and

 

tree[[list(<selectors>)]]

JSONC TOML

 

json <- tsjsonc::ts_parse_jsonc(
  '{ "a": 1, "b": [10, 20, 30], "c": { "c1": true, "c2": null } }'
)
json |> ts_tree_select("b", 1)

#> # jsonc (1 line, 1 selected element)
#> > 1 | { "a": 1, "b": [10, 20, 30], "c": { "c1": true, "c2": null } }

 

json[[list("b", 1)]]

#> [[1]]
#> [1] 10
#>

 

toml <- tstoml::ts_parse_toml(
  '[table]\na = 1\nb = [10, 20, 30]\nc = { c1 = true, c2 = [] }\n'
)
toml |> ts_tree_select("table", "b", 1)

#> # toml (4 lines, 1 selected element)
#>   1 | [table]
#>   2 | a = 1
#> > 3 | b = [10, 20, 30]
#>   4 | c = { c1 = true, c2 = [] }

 

toml[[list("table", "b", 1)]]

#> [[1]]
#> [1] 10
#>

The [[<- replacement operator

The [[<- operator works similarly to the combination of ts_tree_select() and ts_tree_update(), (and also to the replacement function ts_tree_select<-()), but it might be more readable.

JSONC TOML

 

json <- tsjsonc::ts_parse_jsonc(
  '{ "a": 1, "b": [10, 20, 30], "c": { "c1": true, "c2": null } }'
)
json

#> # jsonc (1 line)
#> 1 | { "a": 1, "b": [10, 20, 30], "c": { "c1": true, "c2": null } }

 

json |> ts_tree_select("b", 1)

#> # jsonc (1 line, 1 selected element)
#> > 1 | { "a": 1, "b": [10, 20, 30], "c": { "c1": true, "c2": null } }

 

json[[list("b", 1)]] <- 100
json

#> # jsonc (1 line)
#> 1 | { "a": 1, "b": [100, 20, 30], "c": { "c1": true, "c2": null } }

 

toml <- tstoml::ts_parse_toml(
  '[table]\na = 1\nb = [10, 20, 30]\nc = { c1 = true, c2 = [] }\n'
)
toml

#> # toml (4 lines)
#> 1 | [table]
#> 2 | a = 1
#> 3 | b = [10, 20, 30]
#> 4 | c = { c1 = true, c2 = [] }

 

toml |> ts_tree_select("table", "b", 1)

#> # toml (4 lines, 1 selected element)
#>   1 | [table]
#>   2 | a = 1
#> > 3 | b = [10, 20, 30]
#>   4 | c = { c1 = true, c2 = [] }

 

toml[[list("table", "b", 1)]] <- 100
toml

#> # toml (4 lines)
#> 1 | [table]
#> 2 | a = 1
#> 3 | b = [100.0, 20, 30]
#> 4 | c = { c1 = true, c2 = [] }

See also

Other ts_tree generics: [[<-.ts_tree(), format.ts_tree(), print.ts_tree(), select-set, ts_tree_ast(), ts_tree_delete(), ts_tree_dom(), ts_tree_format(), ts_tree_insert(), ts_tree_new(), ts_tree_query(), ts_tree_select(), ts_tree_sexpr(), ts_tree_unserialize(), ts_tree_update(), ts_tree_write()

Other serialization functions: ts_tree_unserialize()

Examples

# Create a parse tree with tsjsonc -------------------------------------
tree <- tsjsonc::ts_parse_jsonc('{"a": 13, "b": [1, 2, 3], "c": "x"}')

tree
#> # jsonc (1 line)
#> 1 | {"a": 13, "b": [1, 2, 3], "c": "x"}

tree[[list("a")]]
#> [[1]]
#> [1] 13
#> 

# Last two elements of "b"
tree[[list("b", -(1:2))]]
#> [[1]]
#> [1] 2
#> 
#> [[2]]
#> [1] 3
#>