From cd9f3bc3f3ecb04eaee42c65880711bd35c7e71b Mon Sep 17 00:00:00 2001
From: Matthew Hall <hallmatthew314@gmail.com>
Date: Sat, 3 Sep 2022 16:07:58 +1200
Subject: Able to parse Thue code

---
 src/flint.cr        | 31 +++++++++++++++++++------------
 src/thue/parser.cr  | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/thue/program.cr | 13 +++++++++++++
 src/thue/rule.cr    | 43 +++++++++++++++++++++++++++++++++++++++++++
 src/thue/thue.cr    |  7 +++++++
 5 files changed, 132 insertions(+), 12 deletions(-)
 create mode 100644 src/thue/parser.cr
 create mode 100644 src/thue/program.cr
 create mode 100644 src/thue/rule.cr
 create mode 100644 src/thue/thue.cr

(limited to 'src')

diff --git a/src/flint.cr b/src/flint.cr
index f2323a2..8f11223 100644
--- a/src/flint.cr
+++ b/src/flint.cr
@@ -4,10 +4,10 @@ require "option_parser"
 
 require "./util.cr"
 require "./brainfuck/*"
-require "./brainfuck/parser.cr"
+require "./thue/*"
 
 module Flint
-  VERSION = "0.1.0"
+  VERSION = "0.1.1"
 
   def self.main
     execution_mode = :interpret
@@ -23,12 +23,19 @@ module Flint
         chosen_language = :brainfuck
         memory_size = Brainfuck::DEFAULT_TAPE_SIZE
 
-        parser.banner = "Useage: flint brainfuck [OPTIONS] [FILE]"
+        parser.banner = "Usage: flint brainfuck [OPTIONS] [FILE]"
         parser.on("-t CELLS", "--tape-size=CELLS", "specify the number of memory cells in the tape, defaults to 30,000") do |_cells|
           memory_size = _cells.to_i
         end
       end
 
+      parser.on("thue", "select Thue as the language") do
+        chosen_language = :thue
+
+        parser.banner = "Usage: flint thue [OPTIONS] [FILE]"
+        # no thue-specific options yet
+      end
+
       parser.on("-h", "--help", "show this help and exit") do
         puts parser
         exit(0)
@@ -48,12 +55,6 @@ module Flint
 
     parser.parse
 
-    if chosen_language.nil?
-      puts "ERROR: No language chosen"
-      puts parser
-      exit(1)
-    end
-
     if read_stdin
       source_io = STDIN
     elsif source_file
@@ -62,14 +63,20 @@ module Flint
     else
       puts "ERROR: No source file chosen"
       puts parser
-      puts source_file.nil?
-      puts (!read_stdin)
       exit(1)
     end
 
-    if chosen_language == :brainfuck
+    case chosen_language
+    when :brainfuck
       bf_parser = Brainfuck::Parser.new(source_io)
       program = Brainfuck::Program.new(bf_parser, memory_size)
+    when :thue
+      thue_parser = Thue::Parser.new(source_io)
+      program = Thue::Program.new(thue_parser)
+    else
+      puts "ERROR: No language chosen"
+      puts parser
+      exit(1)
     end
 
     begin
diff --git a/src/thue/parser.cr b/src/thue/parser.cr
new file mode 100644
index 0000000..6b3907b
--- /dev/null
+++ b/src/thue/parser.cr
@@ -0,0 +1,50 @@
+require "../util.cr"
+require "./thue.cr"
+require "./rule.cr"
+
+class Thue::Parser
+  def initialize(code_io : IO)
+    @raw_code = code_io.gets_to_end
+    code_io.close # just in case
+  end
+
+  def parse
+    rules = [] of Rule
+    line_iterator = @raw_code.lines.each
+
+    line_iterator.each do |line|
+      case line
+      when "", "::="
+        # stops iteration of lines to be picked up by string builder
+        break
+
+      # returned match objects are provably not_nil, safe
+      when .matches?(R_INPUT_RULE)
+        m = line.match(R_INPUT_RULE).not_nil!
+        rules << InputRule.new(m[1])
+
+      when .matches?(R_OUTPUT_RULE)
+        m = line.match(R_OUTPUT_RULE).not_nil!
+        rules << OutputRule.new(m[1], m[2])
+
+      when .matches?(R_NORMAL_RULE)
+        m = line.match(R_NORMAL_RULE).not_nil!
+        rules << NormalRule.new(m[1], m[2])
+
+      else
+        raise Util::ParserError.new("No separator between code and initial state near '#{line}'")
+      end
+    end
+
+    state = String.build do |str|
+      # resumes from where rule parser left off
+      line_iterator.each do |line|
+        str << line
+        str << '\n'
+      end
+    end
+
+    {rules, state}
+  end
+end
+
diff --git a/src/thue/program.cr b/src/thue/program.cr
new file mode 100644
index 0000000..c59780b
--- /dev/null
+++ b/src/thue/program.cr
@@ -0,0 +1,13 @@
+require "./thue.cr"
+require "./parser.cr"
+
+class Thue::Program
+  def initialize(@parser : Parser)
+  end
+
+  def interpret
+    something = @parser.parse
+    puts something
+  end
+end
+
diff --git a/src/thue/rule.cr b/src/thue/rule.cr
new file mode 100644
index 0000000..34c2396
--- /dev/null
+++ b/src/thue/rule.cr
@@ -0,0 +1,43 @@
+require "./thue.cr"
+
+abstract struct Thue::Rule
+  @pattern : Regex
+
+  def initialize(pattern : String)
+    @pattern = Regex.new(pattern)
+  end
+
+  def matches?(str : String) : Bool
+    str.matches?(@pattern)
+  end
+
+  abstract def replacement : String
+end
+
+struct Thue::NormalRule < Thue::Rule
+  def initialize(pattern : String, @replacement : String)
+    super(pattern)
+  end
+
+  def replacement : String
+    @replacement
+  end
+end
+
+struct Thue::InputRule < Thue::Rule
+  def replacement : String
+    gets
+  end
+end
+
+struct Thue::OutputRule < Thue::Rule
+  def initialize(pattern : String, @output : String)
+    super(pattern)
+  end
+
+  def replacement : String
+    print @output
+    return ""
+  end
+end
+
diff --git a/src/thue/thue.cr b/src/thue/thue.cr
new file mode 100644
index 0000000..9c22b96
--- /dev/null
+++ b/src/thue/thue.cr
@@ -0,0 +1,7 @@
+module Thue
+  # Allow matching empty patterns, handle during parsing
+  R_NORMAL_RULE = /^(.*)::=(.*)$/
+  R_INPUT_RULE = /^(.*)::=:::$/
+  R_OUTPUT_RULE = /^(.*)::=~(.*)$/
+end
+
-- 
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