97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
/*
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Serene --- Yet an other Lisp
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Copyright (c) 2020 Sameer Rahmani <lxsameer@gnu.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package ast
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// The Source data structure is used to track expression back to the source
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// code. For example to find which source (file) they belongs to.
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import (
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"sort"
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"strings"
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)
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var builtinSource *Source
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type Source struct {
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// A Pointer to the buffer where the parser used for parsing the source
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Buffer *[]string
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// The namespace name which this source is describing
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NS string
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// This array contains the boundaries of each line in the buffer. For example
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// [24 50 106] means that the buffer contains 3 lines and the first line can
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// be found from the index 0 to index 24 of the buffer and the second line is
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// from index 25 till 50 and so on
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LineIndex *[]int
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}
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// GetSubstr returns the a pointer to the string from the buffer specified by the `start` and `end`
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func (s *Source) GetSubstr(start, end int) *string {
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if start < len(*s.Buffer) && start >= 0 && end < len(*s.Buffer) && end > 0 && start <= end {
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result := strings.Join((*s.Buffer)[start:end], "")
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return &result
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}
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return nil
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}
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// GetLine returns the line specified by the `linenum` from the buffer. It will return "----" if the
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// given line number exceeds the boundaries of the buffer
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func (s *Source) GetLine(linenum int) string {
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lines := strings.Split(strings.Join(*s.Buffer, ""), "\n")
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if linenum > 0 && linenum <= len(lines) {
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return lines[linenum-1]
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}
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return "----"
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}
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// LineNumberFor returns the line number associated with the given position `pos` in
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// the buffer
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func (s *Source) LineNumberFor(pos int) int {
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if pos < 0 {
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return -1
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}
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result := sort.SearchInts(*s.LineIndex, pos)
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// We've found something
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if result > -1 {
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// Since line numbers start from 1 unlike arrays :))
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result++
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}
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return result
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}
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// GetBuiltinSource returns a pointer to a source that represents builtin
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// expressions
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func GetBuiltinSource() *Source {
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if builtinSource == nil {
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buf := strings.Split("builtin", "")
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lineindex := []int{len(buf) - 1}
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builtinSource = &Source{
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Buffer: &buf,
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NS: "Serene.builtins",
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LineIndex: &lineindex,
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}
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}
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return builtinSource
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}
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