• Rob Pike's avatar
    text/template: better error messages during execution, · 7f4b4c0c
    Rob Pike authored
    They now show the correct name, the byte offset on the line, and context for the failed evaluation.
    Before:
            template: three:7: error calling index: index out of range: 5
    After:
            template: top:7:20: executing "three" at <index "hi" $>: error calling index: index out of range: 5
    Here top is the template that was parsed to create the set, and the error appears with the action
    starting at byte 20 of line 7 of "top", inside the template called "three", evaluating the expression
    <index "hi" $>.
    
    Also fix a bug in index: it didn't work on strings. Ouch.
    
    Also fix bug in error for index: was showing type of index not slice.
    The real previous error was:
            template: three:7: error calling index: can't index item of type int
    The html/template package's errors can be improved by building on this;
    I'll do that in a separate pass.
    
    Extends the API for text/template/parse but only by addition of a field and method. The
    old API still works.
    
    Fixes #3188.
    
    R=golang-dev, dsymonds
    CC=golang-dev
    https://golang.org/cl/6576058
    7f4b4c0c
parse_test.go 12.7 KB