matlab: add step5_tco

2 files changed, 132 insertions, 0 deletions

diff --git a/matlab/Function.m b/matlab/Function.m
new file mode 100644
index 0000000..407fe39
--- /dev/null
+++ b/matlab/Function.m
@@ -0,0 +1,16 @@
+classdef Function < handle
+    properties
+        fn
+        ast
+        env
+        params
+    end
+    methods
+        function f = Function(fn, ast, env, params)
+            f.fn = fn;
+            f.ast = ast;
+            f.env = env;
+            f.params = params;
+        end
+    end
+end
diff --git a/matlab/step5_tco.m b/matlab/step5_tco.m
new file mode 100644
index 0000000..c63e7e4
--- /dev/null
+++ b/matlab/step5_tco.m
@@ -0,0 +1,116 @@
+function step5_tco(varargin), main(varargin), end
+
+% read
+function ret = READ(str)
+    ret = reader.read_str(str);
+end
+
+% eval
+function ret = eval_ast(ast, env)
+    switch class(ast)
+    case 'types.Symbol'
+        ret = env.get(ast);
+    case 'cell'
+        ret = {};
+        for i=1:length(ast)
+            ret{end+1} = EVAL(ast{i}, env);
+        end
+    otherwise
+        ret = ast;
+    end
+end
+
+function ret = EVAL(ast, env)
+  while true
+    if ~iscell(ast),
+        ret = eval_ast(ast, env);
+        return;
+    end
+
+    % apply
+    if isa(ast{1},'types.Symbol')
+        a1sym = ast{1}.name;
+    else
+        a1sym = '_@$fn$@_';
+    end
+    switch (a1sym)
+    case 'def!'
+        ret = env.set(ast{2}, EVAL(ast{3}, env));
+        return;
+    case 'let*'
+        let_env = Env(env);
+        for i=1:2:length(ast{2})
+            let_env.set(ast{2}{i}, EVAL(ast{2}{i+1}, let_env));
+        end
+        env = let_env;
+        ast = ast{3}; % TCO
+    case 'do'
+        el = eval_ast(ast(2:end-1), env);
+        ast = ast{end}; % TCO
+    case 'if'
+        cond = EVAL(ast{2}, env);
+        if strcmp(class(cond), 'types.Nil') || ...
+           (islogical(cond) && cond == false)
+           if length(ast) > 3
+               ast = ast{4}; % TCO
+            else
+               ret = types.nil;
+               return;
+            end
+        else
+            ast = ast{3}; % TCO
+        end
+    case 'fn*'
+        fn = @(varargin) EVAL(ast{3}, Env(env, ast{2}, varargin));
+        ret = Function(fn, ast{3}, env, ast{2});
+        return;
+    otherwise
+        el = eval_ast(ast, env);
+        f = el{1};
+        args = el(2:end);
+        if isa(f, 'Function')
+            env = Env(f.env, f.params, args);
+            ast = f.ast; % TCO
+        else
+            ret = f(args{:});
+            return
+        end
+    end
+  end
+end
+
+% print
+function ret = PRINT(ast)
+    ret = printer.pr_str(ast, true);
+end
+
+% REPL
+function ret = rep(str, env)
+    ret = PRINT(EVAL(READ(str), env));
+end
+
+function main(args)
+    repl_env = Env(false);
+
+    % core.m: defined using matlab
+    ns = core.ns(); ks = ns.keys();
+    for i=1:length(ks)
+        k = ks{i};
+        repl_env.set(types.Symbol(k), ns(k));
+    end
+
+    % core.mal: defined using the langauge itself
+    rep('(def! not (fn* (a) (if a false true)))', repl_env);
+
+    %cleanObj = onCleanup(@() disp('*** here1 ***'));
+    while (true)
+        line = input('user> ', 's');
+        if strcmp(strtrim(line),''), continue, end
+        try
+            fprintf('%s\n', rep(line, repl_env));
+        catch err
+            fprintf('Error: %s\n', err.message);
+            fprintf('%s\n', getReport(err, 'extended'));
+        end
+    end
+end