Chapter 18: Functionslinear-chapter18

1 files changed, 74 insertions, 0 deletions

diff --git a/src/main/java/com/seaofnodes/simple/SB.java b/src/main/java/com/seaofnodes/simple/SB.java
new file mode 100644
index 00000000..6f5a29ee
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/SB.java
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+package com.seaofnodes.simple;
+
+/** Tight/tiny StringBuilder wrapper.
+ *  Short short names on purpose; so they don't obscure the printing.
+ *  Can't believe this wasn't done long, long ago. */
+public final class SB {
+  private final StringBuilder _sb;
+  private int _indent = 0;
+  public SB(        ) { _sb = new StringBuilder( ); }
+  public SB(String s) { _sb = new StringBuilder(s); }
+  public SB p( String s ) { _sb.append(s); return this; }
+  public SB p( float  s ) {
+    if( Float.isNaN(s) )
+      _sb.append( "Float.NaN");
+    else if( Float.isInfinite(s) ) {
+      _sb.append(s > 0 ? "Float.POSITIVE_INFINITY" : "Float.NEGATIVE_INFINITY");
+    } else _sb.append(s);
+    return this;
+  }
+  public SB p( double s ) {
+    if( Double.isNaN(s) )
+      _sb.append("Double.NaN");
+    else if( Double.isInfinite(s) ) {
+      _sb.append(s > 0 ? "Double.POSITIVE_INFINITY" : "Double.NEGATIVE_INFINITY");
+    } else _sb.append(s);
+    return this;
+  }
+  public SB p( char   s ) { _sb.append(s); return this; }
+  public SB p( int    s ) { _sb.append(s); return this; }
+  public SB p( long   s ) { _sb.append(s); return this; }
+  public SB p( boolean s) { _sb.append(s); return this; }
+  // Not spelled "p" on purpose: too easy to accidentally say "p(1.0)" and
+  // suddenly call the autoboxed version.
+  public SB pobj( Object s ) { _sb.append(s.toString()); return this; }
+  public SB i( int d ) { for( int i=0; i<d+_indent; i++ ) p("  "); return this; }
+  public SB i( ) { return i(0); }
+  public SB ip(String s) { return i().p(s); }
+  public SB s() { _sb.append(' '); return this; }
+
+  // Increase indentation
+  public SB ii( int i) { _indent += i; return this; }
+  public SB ii() { return ii(1); }
+  // Decrease indentation
+  public SB di( int i) { _indent -= i; return this; }
+  public SB di() { return di(1); }
+
+  public SB nl( ) { return p(System.lineSeparator()); }
+  // Last printed a nl
+  public boolean was_nl() {
+    int len = _sb.length();
+    String nl = System.lineSeparator();
+    int nlen = nl.length();
+    if( len < nlen ) return false;
+    for( int i=0; i<nlen; i++ )
+      if( _sb.charAt(len-nlen+i)!=nl.charAt(i) )
+        return false;
+    return true;
+  }
+
+  // Delete last char.  Useful when doing string-joins and JSON printing and an
+  // extra separater char needs to be removed:
+  //
+  //   sb.p('[');
+  //   for( Foo foo : foos )
+  //     sb.p(foo).p(',');
+  //   sb.unchar().p(']');  // remove extra trailing comma
+  //
+  public SB unchar() { return unchar(1); }
+  public SB unchar(int x) { _sb.setLength(_sb.length()-x); return this; }
+
+  public SB clear() { _sb.setLength(0); return this; }
+  public int len() { return _sb.length(); }
+  @Override public String toString() { return _sb.toString(); }
+}