Use Forms Directly as Evaluatable Input
Mathematica 6 lets you create arbitrary forms, which can then be used as input—evaluating immediately to the settings they are given.
 In[1]:= ```{\!\(\* TagBox[ DynamicModuleBox[{\$CellContext`f\$\$ = Sin[\$CellContext`x^2], \$CellContext`min\$\$ = 0, \$CellContext`max\$\$ = 2 Pi}, InterpretationBox[ PanelBox[ TagBox[GridBox[{ { StyleBox["\<\"Instant Plot\"\>", StripOnInput->False, FrontFaceColor->RGBColor[0.6, 0., 0.], BackFaceColor->RGBColor[0.6, 0., 0.], GraphicsColor->RGBColor[0.6, 0., 0.], FontWeight->Bold, FontSlant->Italic, FontColor->RGBColor[0.6, 0., 0.]], "\[SpanFromLeft]"}, {"\<\"function:\"\>", InputFieldBox[Dynamic[\$CellContext`f\$\$]]}, {"\<\"min:\"\>", InputFieldBox[Dynamic[\$CellContext`min\$\$]]}, {"\<\"max:\"\>", InputFieldBox[Dynamic[\$CellContext`max\$\$]]} }], "Grid"]], Plot[\$CellContext`f\$\$, {\$CellContext`x, \$CellContext`min\$\$, \ \$CellContext`max\$\$}]], DynamicModuleValues:>{}], Setting[#, {0}]& ]\), \[Integral]Sin[x^2] \[DifferentialD]x, \!\(\* TagBox[ DynamicModuleBox[{\$CellContext`f\$\$ = Sin[\$CellContext`x] + Sin[5 \$CellContext`x], \$CellContext`min\$\$ = 0, \$CellContext`max\$\$ = 10 Pi}, InterpretationBox[ PanelBox[ TagBox[GridBox[{ { StyleBox["\<\"Instant Plot\"\>", StripOnInput->False, FrontFaceColor->RGBColor[0.6, 0., 0.], BackFaceColor->RGBColor[0.6, 0., 0.], GraphicsColor->RGBColor[0.6, 0., 0.], FontWeight->Bold, FontSlant->Italic, FontColor->RGBColor[0.6, 0., 0.]], "\[SpanFromLeft]"}, {"\<\"function:\"\>", InputFieldBox[Dynamic[\$CellContext`f\$\$]]}, {"\<\"min:\"\>", InputFieldBox[Dynamic[\$CellContext`min\$\$]]}, {"\<\"max:\"\>", InputFieldBox[Dynamic[\$CellContext`max\$\$]]} }], "Grid"]], Plot[\$CellContext`f\$\$, {\$CellContext`x, \$CellContext`min\$\$, \ \$CellContext`max\$\$}]], DynamicModuleValues:>{}], Setting[#, {0}]& ]\), \[Integral](Sin[x] + Sin[5 x]) \[DifferentialD]x}```
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