prebirth: More substantial libprebirth

This is a decent start.

* build-aux/bootstrap/libprebirth.js: Add a lot of stuff.  Go look for
  yourself.

build-aux/bootstrap/libprebirth.js

@@ -32,20 +32,79 @@
  * removed as they are rewritten in Prebirth Lisp.
  *
  * By convention, everything is prefixed with `js:' in Prebirth (not `es:',
- * because we're using JavaScript-specific features).  Since
+ * because we're using JavaScript-specific features).  For character
- * non-alphanumeric and non-underscore characters are converted into `$',
+ * transformation rules, see `Compiler#_idFromName' in `prebirth.js'.
- * and all functions are prefixed with '$$' for global uniqueness, this
- * results in a `$$js$' prefix in all of the functions below.
  */
 
+const $h$t = true;
+const $h$f = false;
 
-/**
+const argToArr = args => Array.prototype.slice.call( args );
- * Log to the console
+
- */
+function $$list() { return argToArr( arguments ); }
-function $$js$console()
+
+const _error = str =>
 {
-    console.log.apply( console, arguments );
+    throw Error( str );
+}
+
+const _assertPair = xs =>
+{
+    _assertList( xs );
+
+    if ( xs.length === 0 ) {
+        throw TypeError( "expecting pair" );
+    }
+
+    return true;
+}
+
+const _assertList = xs =>
+{
+    if ( !Array.isArray( xs ) ) {
+        throw TypeError( "expecting list" );
+    }
+
+    return true;
+}
+
+// only false (#f in Scheme) is non-true
+const _truep = x => x !== false;
+
+// ignore obj for now
+const $$error = ( msg, obj ) => _error( msg );
+
+const $$cons = ( item, list ) => _assertList( list ) && [ item ].concat( list )
+const $$car  = xs => _assertPair( xs ) && xs[ 0 ];
+const $$cdr  = xs => _assertPair( xs ) && xs.slice( 1 );
+
+const $$list$7$ = xs => Array.isArray( xs );
+const $$pair$7$ = xs => Array.isArray( xs ) && ( xs.length > 0 );
+
+
+// R7RS string
+const $$substring       = ( s, start, end ) => s.substring( start, end );
+const $$string$_$length = s => s.length;
+const $$string$q$$7$    = ( x, y ) => x === y;
+const $$string$_$ref    = ( s, i ) => s[ i ]
+                              || _error( `value out of range: ${i}`);
+
+// R7RS math
+function $$$p$()
+{
+    return argToArr( arguments ).reduce( ( ( x, y ) => x + y ), 0 );
 }
 
 
+// Node.js stuff
+const fs = require( 'fs' );
+
+// stdin->string
+const $$js$stdin$_$$g$string = () =>
+  fs.readFileSync( '/dev/stdin' ).toString();
+
+const $$js$regexp = ( s, opts ) => new RegExp( s, opts );
+const $$js$match  = ( r, s ) => s.match( r ) || false;
+
+
 /** =============== end of libprebirth =============== **/