1 files changed, 175 insertions, 0 deletions
diff --git a/lua/nvim-paredit-scheme/extension.lua b/lua/nvim-paredit-scheme/extension.lua
new file mode 100644
index 0000000..2eb6f91
--- /dev/null
+++ b/lua/nvim-paredit-scheme/extension.lua
@@ -0,0 +1,175 @@
+-- nvim-paredit extension for scheme
+-- Copyright (C) 2023  Ekaitz Zarraga
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+
+local traversal = require("nvim-paredit.utils.traversal")
+
+-- THIS IS A REFERENCE, UNUSED
+local nodes = {
+    "comment",
+    "block_comment", -- for example, #| something |#
+    "directive", -- for example, #!r6rs
+    "boolean",
+    "character",
+    "string",
+    "escape_sequence", -- escape sequence in string, for example, \n in "abc\n"
+    "number",
+    "symbol", -- identifier
+    "keyword", -- #:identifier
+    "list", -- things surrounded by () or [] or {}
+    "quote", -- '
+    "quasiquote", -- `
+    "syntax", -- #'
+    "quasisyntax", --`
+    "unquote", -- ,
+    "unquote_splicing", -- ,@
+    "unsyntax", -- #,
+    "unsyntax_splicing", -- #,@
+    "vector",
+    "byte_vector",
+}
+
+local forms = {
+    comment = {2, 0},        -- for srfi 62,  #;
+    block_comment = {2, 2},  -- for example, #| something |#
+    string = {1, 1},
+    list = {1, 1},           -- things surrounded by () or [] or {}
+    vector = {2, 1},         -- #(...)
+    byte_vector = {5, 1},    -- #vu8(...)
+    vector = {2, 1},
+}
+
+
+local function find_next_parent_form(current_node)
+    if forms[current_node:type()] then
+        return current_node
+    end
+
+    local parent = current_node:parent()
+    if parent then
+        return find_next_parent_form(parent)
+    end
+
+    return current_node
+end
+
+local function find_parent_comment(node)
+    if node:type() == "comment" then
+        return node
+    end
+    local parent = node:parent()
+
+    if parent then
+        return find_parent_comment(parent)
+    else
+        return nil
+    end
+end
+
+local M = {}
+
+-- Should return the 'root' of the given Treesitter node. For example:
+-- The node at cursor in the below example is `()` or 'list_lit':
+--   '(|)
+-- But the node root is `'()` or 'quoting_lit'
+M.get_node_root = function(node)
+    local search_point = node
+    if M.node_is_form(node) then
+        search_point = node:parent()
+    end
+
+    local root = find_next_parent_form(search_point)
+    return traversal.find_root_element_relative_to(root, node)
+end
+-- This is the inverse of `get_node_root` for forms and should find the inner
+-- node for which the forms elements are direct children.
+--
+-- For example given the node `'()` or 'quoting_lit', this function should
+-- return `()` or 'list_lit'.
+M.unwrap_form = function(node)
+    if forms[node:type()] then
+        return node
+    end
+    local child = node:named_child(0)
+    if child then
+        return M.unwrap_form(child)
+    end
+end
+-- Accepts a Treesitter node and should return true or false depending on
+-- whether the given node can be considered a 'form'
+M.node_is_form = function(node)
+    if M.unwrap_form(node) then
+        return true
+    else
+        return false
+    end
+end
+-- Accepts a Treesitter node and should return true or false depending on
+-- whether the given node can be considered a 'comment'
+M.node_is_comment = function(node)
+    return (find_parent_comment(node)
+    or node:type() == "comment"
+    or node:type() == "block_comment")
+end
+-- Accepts a Treesitter node representing a form and should return the
+-- 'edges' of the node. This includes the node text and the range covered by
+-- the node
+M.get_form_edges = function(node)
+    local node_range = { node:range() }
+
+    local form = M.unwrap_form(node)
+    local form_range = { form:range() }
+
+    -- Get the size of the form boundaries
+    local size = forms[node:type()]
+    if not size then
+        -- default to {1, 1}
+        size = {1, 1}
+    end
+    -- If it's an inline comment don't do anything
+    if node:type() == "comment"
+        and vim.api.nvim_buf_get_text(0, form_range[1], form_range[2],
+        form_range[3], form_range[4], {})[1]:sub(1,1) == ";"
+    then
+        return {}
+    end
+
+    local left_range = { node_range[1], node_range[2] }
+    left_range[3] = form_range[1]
+    left_range[4] = form_range[2] + size[1]
+
+    local right_range = { form:range() }
+    right_range[1] = right_range[3]
+    right_range[2] = right_range[4] - size[2]
+
+    local left_text = vim.api.nvim_buf_get_text(0, left_range[1], left_range[2],
+    left_range[3], left_range[4], {})
+    local right_text = vim.api.nvim_buf_get_text(0, right_range[1],
+    right_range[2], right_range[3], right_range[4], {})
+
+    return {
+        left = {
+            text = left_text[1],
+            range = left_range,
+        },
+        right = {
+            text = right_text[1],
+            range = right_range,
+        },
+    }
+end
+
+return M