Category:Tcl: Difference between revisions
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:''“I got the idea for Tcl while on sabbatical leave at DEC's Western Research Laboratory in the fall of 1987. I started actually implementing it when I got back to Berkeley in the spring of 1988; by summer of that year it was in use in some internal applications of ours, but there was no Tk. The first external releases of Tcl were in 1989, I believe. I started implementing Tk in 1989, and the first release of Tk was in 1991.”'' |
:''“I got the idea for Tcl while on sabbatical leave at DEC's Western Research Laboratory in the fall of 1987. I started actually implementing it when I got back to Berkeley in the spring of 1988; by summer of that year it was in use in some internal applications of ours, but there was no Tk. The first external releases of Tcl were in 1989, I believe. I started implementing Tk in 1989, and the first release of Tk was in 1991.”'' |
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==Grammar== |
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Note that this is a simplified language grammar, and it is normal to think of the language at a higher level where these differences don't show. |
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<br clear=all> |
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script '''::=''' command'''? ((''' “''\n''” '''|''' “'';''” ''')''' script ''')''' |
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command '''::=''' “''#''” characters “''\n''” <span style="color:grey">/* comment */</span> |
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'''|''' word '''(''' space word ''')*''' <span style="color:grey">/* sequence of space-separated words; |
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* first is command name */</span> |
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'''|''' <span style="color:grey">/* empty */</span> |
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word '''::=''' “''{*}''”'''?''' “''{''” characters “''}''” <span style="color:grey">/* braces must be balanced */</span> |
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'''|''' “''{*}''”'''?''' “''"''” charSubsts “''"''” <span style="color:grey">/* double-quotes must be balanced */</span> |
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'''|''' “''{*}''”'''?''' charSubsts |
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charSubsts '''::=''' “''[''” script “'']''” charSubsts'''?''' <span style="color:grey">/* brackets must be balanced */</span> |
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'''|''' “''$''” varName charSubsts'''?''' |
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'''|''' “''${''” varName “''}''” charSubsts'''?''' |
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'''|''' “''\\''” escapeSequence charSubsts''?'' |
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'''|''' ordinaryChar charSubsts''?'' |
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==Language Value Model== |
==Language Value Model== |
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Tcl's value model operates on two levels. |
Tcl's value model operates on two levels. |
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