Base parser

src/Parser.php

@@ -0,0 +1,172 @@
+<?php
+
+namespace jcubic\lip;
+
+use jcubic\lip\Tokenizer;
+use jcubic\lip\Symbol;
+use jcubic\lip\Pair;
+
+class Parser {
+    private function pop_join() {
+        $len = count($this->stack);
+        $top = $this->stack[$len - 1];
+        if (is_array($top) && $top[0] instanceof Symbol &&
+            in_array($top[0]->name, $this->special_forms) &&
+            $len > 1 && !$top[0]->literal) {
+            array_pop($this->stack);
+            $len = count($this->stack);
+            $last = $stack[$len - 1];
+            if (is_array($last) && count($last) > 1 &&
+                $last[0] instanceof Symbol) {
+                $last[] = $top;
+            } else if ($len == 0) {
+                $this->stack[$len - 1] = $top;
+            } else if ($last instanceof Pair) {
+                if ($last->cd instanceof Pair) {
+                    $this->stack[$len - 1] = new Pair(
+                        $last,
+                        Pair::fromArray($top)
+                    );
+                } else {
+                    $this->stack[$len - 1]->cdr = Pair::fromArray($top);
+                }
+            } else {
+                $last[] = $top;
+            }
+        }
+    }
+    // -------------------------------------------------------------------------
+    private function reset() {
+        $this->special_tokens = array_keys(Tokenizer::$specials);
+        $this->stack = array();
+        $this->special = null;
+        $this->special_forms = array_values(Tokenizer::$specials);
+        $this->parents = 0;
+        $this->first_value = false;
+        $this->specials_stack = array();
+        $this->single_list_specials = array();
+        $this->special_count = 0;
+    }
+    // -------------------------------------------------------------------------
+    private parse_value($value) {
+        /* TODO: write code from parse_argument */
+        return $value;
+    }
+    // -------------------------------------------------------------------------
+    public function parse($tokens) {
+        if (is_string($tokens)) {
+            throw new Exception("parse require tokenized array of tokens not string");
+        }
+        $result = array();
+        $this->reset();
+        foreach ($tokens as $token) {
+            $len = count($this->stack);
+            $top = $len == 0 ? null : $this->stack[$len - 1];
+            if (in_array($token, $this->special_tokens)) {
+                $this->special_count++;
+                $this->special = $token;
+                $this->stack[] = array($self::specials[$this->special]);
+                if (!$this->special) {
+                    $this->single_list_specials = array();
+                }
+                $this->single_list_specials[] = $this->special;
+            } else {
+                if ($this->special != null) {
+                    $this->specials_stack[] = $this->single_list_specials;
+                    $this->single_list_specials = array();
+                }
+                if ($token == '(') {
+                    $this->first_value = true;
+                    $this->parents++;
+                    $this->stack[] = array();
+                    $this->special = null;
+                    $this->special_count = 0;
+                } else if ($token == '.' && !$this->first_value) {
+                    $this->stack[count($this->stack) - 1] = Pair::fromArray($top);
+                } else if ($token == ')') {
+                    $this->parents--;
+                    if ($len == 0) {
+                        throw new Exception("Unbalanced parenthesis");
+                    }
+                    if ($len == 1) {
+                        $result[] = array_pop($this->stack);
+                    } else if ($len > 1) {
+                        $list = array_pop($this->stack);
+                        $len = count($this->stack);
+                        $top = $this->stack[$len - 1];
+                        if (is_array($top)) {
+                            $this->stack[$len - 1][] = $list;
+                        } else if ($top instanceof Pair) {
+                            $top->append(Pair::fromArray($list));
+                        }
+                        if (count($this->specials_stack) > 0) {
+                            $this->single_list_special = array_pop($this->specials_stack);
+                            while (count($this->single_list_special) > 0) {
+                                $this->pop_join();
+                                array_pop($this->single_list_special);
+                            }
+                        } else {
+                            $this->pop_join();
+                        }
+                    }
+                    if ($this->parents == 0 && count($this->stack) > 0) {
+                        $result[] = array_pop($this->stack);
+                    }
+                } else {
+                    $this->first_value = false;
+                    $value = $this->parse_value($token);
+                    $len = count($this->stack);
+                    if ($this->special && $this->special_count > 0) {
+                        while ($this->special_count--) {
+                            $this->stack[$len][] = $value;
+                            $value = array_pop($this->stack);
+                        }
+                        array_pop($this->specials_stack);
+                        $this->special_count = 0;
+                        $this->special = false;
+                    } else if ($value instanceof Symbol &&
+                               in_array($value->name, $this->special_tokens)) {
+                        $value->literal = true;
+                    }
+                    $len = count($this->stack);
+                    $top = $this->stack[$len - 1];
+                    if ($top instanceof Pair) {
+                        $node = $top;
+                        while (true) {
+                            if (Pair::isNil($node->cdr)) {
+                                if (is_array($value)) {
+                                    $node->cdr = Pair::fromArray($value);
+                                } else {
+                                    $node->cdr = $value;
+                                }
+                                break;
+                            } else {
+                                $node = $node->cdr;
+                            }
+                        }
+                    } else if ($len == 0) {
+                        $result[] = $value;
+                    } else {
+                        $this->stack[$len - 1][] = $value;
+                    }
+                }
+            }
+        }
+        $parntesis = array_filter($tokens, function($t) {
+            return preg_match("/^[()]$/", $t);
+        });
+        if (count($parntesis) == 0 && count($this->stack) > 0) {
+            $result = array_merge($result, $stack);
+            $this->stack = [];
+        }
+        if (count($this->stack) > 0) {
+            throw new Exception("Unbalanced parenthesis 2");
+        }
+        return array_map(function($arg) {
+            if (is_array($arg)) {
+                return Pair::fromArray($arg);
+            }
+            return $arg;
+        }, $result);
+    }
+}

src/Tokenizer.php

@@ -106,6 +106,4 @@ static function init() {
     }
 }
 
-Tokenizer::init();
-
-?>
+Tokenizer::init();

src/utils.php

@@ -48,7 +48,7 @@ function getGlobalVar($name) {
     }
 }
 
-
+// ---------------------------------------------------------------------------------------
 function lastItem($array, $n = 1) {
     return $array[count($array) - $n];
 }