Entering edit mode
                    Hi, I thought one can affect how ShortRead's readAligned function handles reverse strand BAM reads: to reverse complement them, or not, with the ScanBamParam reverseComplement. I'm not able to do that, can you set me straight? Thank you, see the code below.
library(ShortRead)
b = readAligned('my.bam', type='BAM')
sread(b)
[1]   151 CATTGCTTCCGTTTGTGCTCGATAAAAATAAGAAT...GTCTGGTTCATCATCTGTAAGAATGGCTTCCAGAG
# reverseComplement: A logical(1) vectors. BAM files store reads mapping
#          to the minus strand as though they are on the plus strand.
#          Rsamtools obeys this convention by default
#          (‘reverseComplement=FALSE’), but when this value is set to
#          TRUE returns the sequence and quality scores of reads mapped
#          to the minus strand in the reverse complement (sequence) and
#          reverse (quality) of the read as stored in the BAM file. This
#          might be useful if wishing to recover read and quality scores
#          as represented in fastq files, but is NOT appropriate for
#          variant calling or other alignment-based operations.
param.T = ScanBamParam(simpleCigar = TRUE, reverseComplement = TRUE,
     what = ShortRead:::.readAligned_bamWhat())
b.SBP.TRUE = readAligned('my.bam', type='BAM', param=param.T)
sread(b.SBP.TRUE)
[1]   151 CATTGCTTCCGTTTGTGCTCGATAAAAATAAGAAT...GTCTGGTTCATCATCTGTAAGAATGGCTTCCAGAG
param.F = ScanBamParam(simpleCigar = TRUE, reverseComplement = FALSE,
     what = ShortRead:::.readAligned_bamWhat())
b.SBP.FALSE = readAligned('my.bam', type='BAM', param=param.F)
Warning message:
UserArgumentMismatch
  using 'TRUE' for 'bamReverseComplement(param)' 
sread(b.SBP.FALSE)
[1]   151 CATTGCTTCCGTTTGTGCTCGATAAAAATAAGAAT...GTCTGGTTCATCATCTGTAAGAATGGCTTCCAGAG
> version
               _                                                 
platform       x86_64-unknown-linux-gnu                          
arch           x86_64                                            
os             linux-gnu                                         
system         x86_64, linux-gnu                                 
status         Under development (unstable)                      
major          3                                                 
minor          2.0                                               
year           2015                                              
month          01                                                
day            11                                                
svn rev        67421                                             
language       R                                                 
version.string R Under development (unstable) (2015-01-11 r67421)
nickname       Unsuffered Consequences
                          
> sessionInfo()
R Under development (unstable) (2015-01-11 r67421)
Platform: x86_64-unknown-linux-gnu (64-bit)
Running under: Ubuntu 14.04.1 LTS
locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
attached base packages:
[1] stats4    parallel  stats     graphics  grDevices utils     datasets  methods  
[9] base     
other attached packages:
 [1] ShortRead_1.25.8         GenomicAlignments_1.3.23 Rsamtools_1.19.26       
 [4] GenomicRanges_1.19.33    GenomeInfoDb_1.3.12      Biostrings_2.35.7       
 [7] XVector_0.7.3            IRanges_2.1.35           S4Vectors_0.5.16        
[10] BiocParallel_1.1.11      BiocGenerics_0.13.4      BiocInstaller_1.17.3    
loaded via a namespace (and not attached):
 [1] base64enc_0.1-2     BatchJobs_1.5       BBmisc_1.8         
 [4] Biobase_2.27.1      bitops_1.0-6        brew_1.0-6         
 [7] checkmate_1.5.1     codetools_0.2-9     DBI_0.3.1          
[10] digest_0.6.8        fail_1.2            foreach_1.4.2      
[13] grid_3.2.0          hwriter_1.3.2       iterators_1.0.7    
[16] lattice_0.20-29     latticeExtra_0.6-26 RColorBrewer_1.1-2 
[19] RSQLite_1.0.0       sendmailR_1.2-1     stringr_0.6.2      
[22] tools_3.2.0         zlibbioc_1.13.0    

Oops, I forgot to note
b = readAligned('my.bam', type='BAM')
strand(b)
[1] -
Levels: + - *
Also, I can get what I want with e.g.
bsr = sread(b)
ndx = strand(b)=='-' & !is.na(strand(b))
bsr[ndx] = reverseComplement(bsr[ndx])