Add back line datastructure

Author: fritzo

README.md

@@ -20,7 +20,7 @@ Syntax tools for the
 
 ### Data Formats <a name="formats"/>
 
-This module deals with three formats of data.
+This module deals with four formats of data.
 
 1.  Codes - Immutable space-delimited lists of tokens.
 
@@ -38,7 +38,28 @@ This module deals with three formats of data.
 
         "ASSERT EQUAL APP VAR two I I"
 
-2.  Terms - Immutable array-representations of abstract syntax trees.
+2.  Lines - Immutable objects with a `code` field and
+    a `name` field that is either `null` or a string.
+    Each line is either an assertion or a definition;
+    assertions have `name = null` and definitions define `name` by their `code`.
+
+    **JSON Serializable:** yes
+
+    **Examples:**
+
+        // a definition
+        {
+            "name": "two",
+            "code": "LAMBDA VAR f LAMBDA VAR x APP VAR f APP VAR x VAR x"
+        }
+
+        // an assertion
+        {
+            "name": null,
+            "code": "EQUAL APP VAR two I I"
+        }
+
+3.  Terms - Immutable array-representations of abstract syntax trees.
 
     **JSON Serializable:** yes
 
@@ -62,7 +83,7 @@ This module deals with three formats of data.
             ]
         ]
 
-3.  Trees - Mutable cross-linked abstract syntax trees for easy traversal.
+4.  Trees - Mutable cross-linked abstract syntax trees for easy traversal.
 
     **JSON Serializable:** no, because of cycles
 
@@ -91,6 +112,8 @@ Signature:
     compiler.parse : string -> term
     compiler.load : code -> term  // compatible with pomagma analyst
     compiler.dump : term -> code  // compatible with pomagma analyst
+    compiler.loadLine : line -> term
+    compiler.dumpLine : term -> line
     compiler.enumerateFresh : int -> string (a variable name)
     compiler.substitute : name * term * term -> nil
     compiler.parenthesize : term -> term

lib/compiler.js

@@ -11,6 +11,31 @@ var test = require('./test').suite('compiler');
 var parse = serialize.parser();
 var print = serialize.printer();
 
+var parseLine = function (line) {
+    var name = line.name;
+    var body = parse(line.code);
+    if (name !== null) {
+        return DEFINE(VAR(name), body);
+    } else {
+        return ASSERT(body);
+    }
+};
+
+var printLine = function (term) {
+    var token = term[0];
+    if (token === 'ASSERT') {
+        return {
+            token: null,
+            code: print(term[1])
+        };
+    } else if (token === 'DEFINE') {
+        return {
+            name: term[1][1],
+            code: print(term[2])
+        };
+    }
+};
+
 //----------------------------------------------------------------------------
 // Symbols
 
@@ -1409,6 +1434,16 @@ module.exports = {
         var curryTerm = compile(churchTerm);
         return print(curryTerm);
     },
+    loadLine: function (line) {
+        var curryTerm = parseLine(line);
+        var churchTerm = decompile(curryTerm);
+        return churchTerm;
+    },
+    dumpLine: function (churchTerm) {
+        var curryTerm = compile(churchTerm);
+        var line = printLine(curryTerm);
+        return line;
+    },
     enumerateFresh: fresh.enumerate,
     substitute: substitute,
     parenthesize: parenthesize,

package.json

@@ -1,6 +1,6 @@
 {
   "name": "puddle-syntax",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "Syntax tools for the Puddle coding environment",
   "main": "index.js",
   "dependencies": {

test/lib/datasets.js

@@ -12,10 +12,12 @@ var codes = stats.sampleUnique(grammar.sampleCode, SAMPLE_COUNT);
 var curryTerms = _.map(codes, compiler.parse);
 var churchTerms = _.map(codes, compiler.load);
 var nodes = _.map(churchTerms, tree.load);
+var lines = _.map(churchTerms, compiler.dumpLine);
 
 module.exports = {
     codes: codes,
     curryTerms: curryTerms,
     churchTerms: churchTerms,
     nodes: nodes,
+    lines: lines,
 };