The char/1 parser is a terminal parser that matches a specific character.

Examples

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?H)
iex> assert %Context{status: :ok, ast: ?H, input: "ello World", index: 1, line: 1, col: 2} = Ergo.parse(parser, "Hello World")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?h)
iex> assert %Context{status: {:error, [{:unexpected_char, {1, 1}, "Expected: |h| Actual: |H|"}]}, input: "Hello World"} = Ergo.parse(parser, "Hello World")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?H)
iex> assert %Context{status: {:error, [{:unexpected_eoi, {1, 1}, "Unexpected end of input"}]}} = Ergo.parse(parser, "")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?A..?Z)
iex> assert %Context{status: :ok, ast: ?H, input: "ello World", index: 1, line: 1, col: 2} = Ergo.parse(parser, "Hello World")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?a..?z)
iex> assert %Context{status: {:error, [{:unexpected_char, {1, 1}, "Expected: |a|..|z| Actual: |H|"}]},input: "Hello World"} = Ergo.parse(parser, "Hello World")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(?A..?Z)
iex> assert %Context{status: {:error, [{:unexpected_eoi, {1, 1}, "Unexpected end of input"}]}} = Ergo.parse(parser, "")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char([?a..?z, ?A..?Z])
iex> assert %Context{status: :ok, ast: ?H, input: "ello World", index: 1, line: 1, col: 2} = Ergo.parse(parser, "Hello World")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char([?a..?z, ?A..?Z])
iex> assert %Context{status: {:error, [{:unexpected_char, {1, 1}, "Expected: [|a|..|z|, |A|..|Z|] Actual: |0|"}]}, input: "0000"} = Ergo.parse(parser, "0000")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(-?0)
iex> assert %Context{status: {:error, [{:unexpected_char, {1, 1}, "Should not have matched |0|"}]}, input: "0000"} = Ergo.parse(parser, "0000")

iex> alias Ergo.Context
iex> import Ergo.Terminals
iex> parser = char(-?a)
iex> assert %Context{status: :ok, input: "000", ast: ?0, index: 1, col: 2} = Ergo.parse(parser, "0000")